Parliamentary war powers and the role of international law in foreign troop deployment decisions: The US-led coalition against “Islamic State” in Iraq and Syria

Abstract

This article addresses the degree of parliamentary involvement in decisions to deploy armed forces abroad. It observes how the recourse to force by the US-led military coalition fighting against the so-called Islamic State (IS, also known as ISIL, or Da’esh) in Iraq and Syria seems to fit into a broader trend of increased parliamentary control over war-and-peace decisions on both sides of the Atlantic. Inasmuch as international legal arguments can and do play a role in parliamentary debates and concomitant resolutions, this trend carries the potential of contributing to the compliance pull of the jus ad bellum. Against this background, the article explores to what extent newfound war powers on the part of national parliaments go hand in hand with recourse to international legal arguments. The article engages this question through an analysis of the dialogue between the executive and legislative branches in a number of countries (in particular Belgium, the Netherlands, France, Germany, the United Kingdom, and Canada) pertaining to the participation in the US-led coalition against IS.

1. Introduction

Following the rapid advance of the so-called Islamic State (IS, also known as ISIL, or Da’esh) in Iraq and Syria, and pursuant to a request from Baghdad,¹ the United States in September 2014 took the initiative to establish a military coalition conducting air raids against IS.² Numerous countries have since joined the coalition, also known as Operation “Inherent Resolve,” albeit many states provide logistical support or training only.³ Apart from the United States and a range of Arab countries, several Western states decided to actively participate in the offensive against IS by deploying aircraft, namely, Australia, Belgium, Canada, Denmark, France, and the Netherlands. Contrary to the US and Arab coalition members, however, the latter countries initially limited their actions to Iraqi territory only.⁴ It was only in the course of 2015–2016 that these countries gradually expanded their scope of operations to Syrian territory as well.⁵ While not conducting air raids as such, Germany has also, since December 2015, provided support to the coalition in the form of reconnaissance and refueling aircraft. Combined with ground operations by the Iraqi army, the US-led military coalition has contributed substantially to weakening IS and strongly reducing its territorial basis. Four years after its initial launch, however, Operation Inherent Resolve remains ongoing.

An interesting feature of the US-led military coalition against IS, and which is the focus of this article, is the high degree of involvement⁶ of national parliaments in the decision-making process pertaining to individual states’ participation in this coalition. Section 2 explains how there has for some time effectively been a general trend toward greater parliamentary involvement in decisions to deploy troops into combat situations abroad. Section 3 illustrates how Operation Inherent Resolve confirms that trend by examining parliamentary involvement in, and support for, decisions in Western states (on both sides of the Atlantic) to actively take part in the US-led coalition against IS. Section 4 subsequently examines how the trend toward greater parliamentary control can and does go hand in hand with increased recourse to international legal arguments at the domestic level—a development which holds the potential of strengthening the compliance pull of the international legal framework. Finally, section 5 more specifically explores the recourse to international legal arguments in parliamentary debates in the period 2014–2016 pertaining to Operation Inherent Resolve, and presents some tentative observations in this respect.

It is noted that the analysis of Operation Inherent Resolve is limited to Western members of the US-led coalition that took or are taking active part in the operation, in particular by contributing aircraft to the military effort—even though, for instance, the parliaments of Russia and Turkey also gave their respective governments the green light for purposes of engaging in military operations in Syria.⁷ The reason for this limitation is threefold. First, coalition members that provide lesser degrees of support or that provide, for instance, training for the Iraqi military, are left out of the equation, since such demarches are normally not caught by the scope of parliamentary war powers (seeAppendix 1)—even though they may at times fall within the scope of the prohibition on the use of force, as reflected in article 2(4) of the United Nations Charter,⁸ or the broader non-intervention principle under customary international law.⁹ Second, the analysis is limited to genuine parliamentary democracies, specifically those that score at least “high” or “very high” on the Global Democracy Ranking.¹⁰ As argued in section 5, international legal arguments are most likely to be raised, and have an impact, in established democracies. As a consequence, parliamentary democracies are the most relevant cases for this article. Third, the limitation is inspired by practical considerations, chiefly the public availability of parliamentary records and linguistic concerns.¹¹Appendix 1 provides a schematic overview of parliamentary involvement in military deployments in the countries concerned.

2. The general trend toward increased parliamentary involvement in decisions to deploy troops abroad

Already in the 1990s, Lori Fisler Damrosch drew attention to a general trend “towards parliamentary control over the decision to introduce troops into situations of actual or potential hostilities.”¹² The increasing parliamentary involvement in a domain long reserved by and large to the executive branch is evident from the fact that governments have frequently sought parliamentary approval or have engaged in more frequent consultations with the legislative branch, even in the absence of a binding obligation thereto (at least in the executive’s view¹³).¹⁴ With regard to the 1991 Gulf War, Damrosch identified a striking pattern of parliamentary approvals for decisions to commit military support, including votes in the US Congress, the French Assemblée Nationale, and the Parliaments of Italy, Canada, Australia, the Netherlands, Greece, Turkey, and Spain.¹⁵ When NATO launched Operation Allied Force against the then Federal Republic of Yugoslavia in 1999, intensive parliamentary deliberations similarly took place in all participating states.¹⁶

In the wake of the 1999 Kosovo intervention and the 2003 US-led intervention in Iraq—notably two interventions whose legality under international law was highly contested—initiatives were moreover undertaken in various countries to formally upgrade national parliaments’ involvement in this domain.¹⁷ Thus, in the Netherlands, the Constitution was revised in the year 2000, to oblige the government to at least inform parliament prior to the deployment of armed forces abroad.¹⁸ In 2005, Spain adopted the Ley Defensa Nacional, stipulating that foreign troop deployments that do not directly relate to the defense of Spain or its national interests require the prior approval of the Congreso de los Diputados.¹⁹ Furthermore, building upon the German Constitutional Court’s 1994 judgment interpreting the Grundgesetz as requiring every armed operation to be approved by parliament (notwithstanding the lack of an explicit obligation to this end in the Grundgesetz),²⁰ the Bundestag in 2005 adopted the so-called Parliamentary Participation Act, further defining its precise role vis-à-vis the deployment of the armed forces abroad.²¹ What makes the German case fairly unique, moreover, is that the Constitutional Court has on multiple occasions verified whether the executive branch complied with its duty to have military operations approved by parliament.²² And in France, the Constitution was amended in 2008 to strengthen the role of Parliament, which had hitherto been limited to cases involving a declaration of war.²³ Furthermore, in the UK, Australia, New Zealand, and Canada, where war prerogatives are traditionally reserved exclusively to the executive branch, recent governments have repeatedly brought military missions before parliament for votes of support or approval.²⁴ In particular, while a legislative initiative in the UK under Prime Minister Gordon Brown²⁵ to consolidate this evolution was not taken further, the British government in 2011 “acknowledged that a convention had developed in Parliament that before troops were committed, the House of Commons should have an opportunity to debate the matter and said that it proposed to observe that convention except when there was an emergency and such action would not be appropriate.”²⁶ Finally, in the United States, rather than to press the outer bounds of their constitutional power, “presidents have tended to seek statutory authorizations to use force when engaging in conflicts of any magnitude, particularly those involving large-scale use of ground troops.”²⁷

Several factors may account for the growing involvement of the legislative branch in these matters. Such factors may include, for instance, national parliaments’ leverage through their “power of the purse,”²⁸ or the increased awareness on the part of the executive branch, in an age where the domestic public has become ever more casualty-averse and increasingly sensitive to reports of collateral damage reported in the media, of the importance of a public and transparent process of legislative deliberation, which can help prepare the polity to accept the risks and burdens of military involvement.²⁹ The controversy surrounding the 2003 Iraq intervention, which in several countries left domestic constituencies and their elected representatives with the feeling that there was insufficient deliberation and that they had been misled, arguably played a catalyst role.³⁰ The 2003 intervention in Iraq notably spurred the creation of national commissions of inquiry, tasked with critically examining the decision to intervene, including by scrutinizing the interaction between the executive and legislative branches.³¹

Notwithstanding this trend, it is evident that democracies still exhibit considerable variation in the actual involvement of parliaments in military deployment decisions—parliamentary “involvement” in foreign troop deployments indeed means different things in different countries. First, in some countries, national (constitutional) law stipulates that parliament must be informed (only) after an operation has been launched (Belgium), or must be informed and “consulted” prior to a foreign troop deployment (the Netherlands). In other countries, military operations abroad must be formally approved by the legislature from the very outset (Germany, Denmark), or must be approved if the operation continues past a certain duration (e.g. 60/90 days in the United States).³² In France, the Elysée must inform parliament about troop deployment decisions within three days after the beginning of an operation but requires parliamentary authorization for purposes of prolonging operations beyond a period of four months. While in most continental European countries, as well as in the USA, parliamentary war powers are defined in the national constitution or separate legislation, as mentioned above in the United Kingdom an unwritten “convention” has recently emerged according to which Parliament must be consulted ahead of foreign troop deployment decisions. A de facto practice of consulting Parliament and holding votes for combat missions has moreover taken hold in Canada, albeit that successive governments have insisted that this practice should not be understood to reflect a legal obligation.³³

Second, it must also be recalled that the “trigger” of parliamentary war powers (inasmuch as they exist) may differ strongly from one country to another—and does not necessarily coincide with the scope of application of the prohibition on the use of force in article 2(4) of the UN Charter. Apart from the existence of thresholds in terms of the duration of an operation (seeAppendix 1), the type of acts that trigger parliamentary “war powers” may also diverge. The Belgian Constitution, for instance, still links the duty to inform parliament to the occurrence of a “state of war,” thus clinging on to a vocabulary that has by and large been abandoned in international law.³⁴ By contrast, in other countries, the role of parliament is linked to the deployment of the armed forces in “armed operations,” “combat missions,” or “offensive military operations” (compare Germany, Canada, and the UK).³⁵ The US War Powers Resolution refers to the introduction of US Armed Forces into “hostilities or into situations where imminent involvement in hostilities is clearly indicated by the circumstances” (section 2(a)). The Danish Constitution refers to the “use of military force against any foreign State” (section 19(2)).

Third, parliamentary “war powers” (anachronistic though that epithet may be) are seldom absolute: even where national parliaments must be consulted or must formally authorize troop deployments abroad, exception is often (and understandably) made—whether in domestic legislation or case law—for situations of urgency—for example, to defend the state against an armed attack—or situations that require a degree of secrecy.³⁶

In the end, whatever the reasons, and notwithstanding the various shapes it takes at the domestic level, the trend toward increased parliamentary involvement is clear. As is explained in the following section, this trend moreover finds confirmation in the national decision-making processes in western states pertaining to their participation in Operation Inherent Resolve.

3. National parliaments and the participation of western states in the US-led coalition against IS: An overview

When, preceding the launch of Operation Inherent Resolve, the United Kingdom, France, and the United States in August–September 2013 hinted at possible air strikes against the Assad regime in reaction to a chemical weapons attack near Damascus,³⁷ British Prime Minister Cameron decided to seek the approval of the House of Commons for a military operation, notwithstanding the absence of a statutory obligation to this end. Remarkably, the motion was defeated by 285 votes to 272. In what some regarded as a gross political miscalculation on the part of Downing Street, the British parliament thus rejected government military action for the first time since 1782 (at the time of the US war on independence). Cameron accepted his defeat, acknowledging that Parliament “[did] not wish to see British military action.”³⁸ Until the launch of the US-led operation against IS in the second half of 2014, the UK Foreign Secretary would assert that “Britain will not be taking part in any air strikes in Syria. We have already had that discussion in our parliament last year and we won’t be revisiting that position.”³⁹

On the other side of the Atlantic too, President Obama in September 2013 sought approval from Congress on a temporary “Authorization for the Use of Military Force against the Government of Syria to Respond to Use of Chemical Weapons.”⁴⁰ Although President Obama repeatedly asserted that he was not legally required to seek Congressional approval, faced with political pressure, he nonetheless considered that “it was right in the absence of a direct or imminent threat to our security, to take this debate to Congress.”⁴¹ While the resolution was approved by the Senate Foreign Relations Committee, it reportedly faced strong opposition in the full Senate as well as in the House of Representatives.⁴² Eventually, plans for military strikes against the Assad regime were shelved after Russia brokered a diplomatic deal over the destruction of Syria’s chemical weapons stockpiles. The decision to go to Congress has nonetheless been considered “perplexing” given that “all of the available evidence suggests that Obama would have lost, and lost badly, any congressional vote on military action.”⁴³

With regard to the actual US-led coalition against IS in Iraq and Syria launched one year later, the executive branches in numerous countries again turned to the legislative branch for support. Unlike the proposed recourse to force against the Assad regime, the quest for parliamentary backing proved much more successful this time around. For example, both in Belgium⁴⁴ and Canada,⁴⁵ the executive branch in 2014 sought—and obtained—the approval of the legislative branch for military actions in Iraq, even though in neither country was this constitutionally required. Later on, the government’s plan to expand military operations to Syria was similarly submitted to, and approved by, their respective parliaments.⁴⁶

Similarly, the Danish deployment in Iraq and, two years later, in Syria also obtained the green light from parliament.⁴⁷ Moreover, both the British and German governments obtained parliamentary approval for operations in Iraq,⁴⁸ and subsequently for expanding military action to Syria.⁴⁹ In accordance with article 35 of the Constitution, the French government informed the Assemblée Nationale shortly after its decision to strike IS targets in Iraq⁵⁰ and received permission from parliament to continue its air campaign after the expiry of the four-month deadline (seeAppendix 1).⁵¹ The same procedure was repeated when France expanded aerial sorties to Syrian territory.⁵² In the Netherlands, the government informed parliament of its decision to participate in the coalition against IS, on Iraqi soil, pursuant to article 100 of the Constitution in September 2014.⁵³ It did the same with regard to the expansion of military operations to Syria on January 29, 2016.⁵⁴

Meanwhile in the United States, President Obama insisted that existing Statutes—specifically the 2001 Authorization for Use of Military Force resolution (AUMF), adopted by Congress in the wake of the 9/11 terrorist attacks—implicitly provided him with ample authority under domestic law to engage in airstrikes against IS in Iraq and Syria.⁵⁵ Interestingly, in spite hereof, President Obama nevertheless submitted a proposal to Congress on February 11, 2015, for a new resolution expressly authorizing the use of military force against IS.⁵⁶ Amidst political opposition on both sides of the aisle, however, the proposal was not taken further in Congress.⁵⁷ Subsequent attempts to amend or appeal the AUMF have remained without success. Meanwhile, Congress has continued to appropriate funds for the ongoing conflict.⁵⁸

Only in Australia, where there is neither domestic legislation nor any unwritten “convention” providing for any (even modest) war powers on the part of the legislative branch,⁵⁹ was parliament completely kept out of the decision-making process: neither the initial Australian participation in 2014 nor the expansion of the scope of operations to Syrian territory in September 2015 led to any form of consultation by the government of the legislative branch (beyond a mere notification)—to the ostensible discontent of an independent MP, the Green Party, and later (in 2015) also of the Labour opposition.⁶⁰ In all, the Australia case strikes as the exception that proves the rule.

4. Parliamentary involvement and the relevance of international legal considerations in domestic use of force decisions

The importance of the outlined trend toward increased parliamentary war powers should not be underestimated. Stronger parliamentary involvement is certainly desirable from a democratic oversight perspective (even if governments need to preserve sufficient leeway to respond (in self-defense) when the state is confronted with an armed attack, or when there is a need for urgent hostage rescue operations or non-combatant evacuation operations). It increases the democratic accountability of the government’s actions in the international arena. While it may usefully assist the executive in garnering the symbolic capital it needs to legitimize military operations abroad, turning to parliament can have other important repercussions as well. In the extreme, as in the UK in 2013, it may force the executive (if not legally, than at least politically) to abandon (at least temporarily) envisaged deployments. More often, the legitimacy benefit derived from a parliamentary endorsement may come at the cost of more or less far-reaching restrictions in terms of the locus of deployment (consider the original parliamentary resolutions in Belgium and Canada authorizing military action against IS in Iraq only), the duration of the deployment,⁶¹ the number of troops, etc., which the government will be unable (whether for domestic legal or political reasons) to set aside at a later stage without again turning to parliament.

Furthermore, if governments decide to seek parliamentary approval absent a formal legal obligation thereto, such practice arguably creates certain expectations on the part of parliament and the domestic audience in general. In particular, the British Government’s defeat over military action in Syria in August 2013 “arguably strengthened [the] emerging convention [to consult the House of Commons], with many commentators suggesting that any future significant deployment of the Armed Forces would now be inconceivable without prior recourse to Parliament.”⁶² The episode thus resulted in an “informal veto” on the part of the House of Commons over the exercise of the executive’s military deployment prerogative.⁶³ Absent formal recognition or incorporation of such upgraded role for the legislative branch, the trend is, however, not necessarily linear in each and every country. Thus, in Canada, while the executive branch admittedly continued the practice of consulting parliament ahead of launching combat operations, both the Harper and Trudeau governments were keen to stress that there was no constitutional, statutory or even conventional obligation to this end.⁶⁴ Similarly, while the Belgian demissionary cabinets sought parliamentary approval for participation in multilateral operations in Libya (2011) and Iraq (2014), after new elections were held the successor government took the position that parliamentary approval was not legally required in order to expand the Belgian operations against IS to Syrian territory (although the Chambre des Représentants did vote a resolution supporting the expansion).⁶⁵ This was denounced by one MP as “turning back the clock.”⁶⁶ By the same token, US President Obama’s initial efforts to seek approval from Congress for military operations against the Assad regime in 2013 (following the chemical weapons attack near Damascus) were not reiterated when President Trump ordered an air strike against a Syrian airbase in April 2017.⁶⁷ Nor were the respective national parliaments consulted when the United States, France, and the United Kingdom conducted similar strikes against Syrian installations in April 2018.⁶⁸

Another consequence is that, as governments are increasingly compelled to present their case for military deployment before parliament, they cannot restrict their pleadings to political arguments, dealing with the economic costs or the risk of casualties, but will also couch their arguments in legal terms. Indeed, although parliaments are by nature political bodies and although the voting behavior of individual members can to a great extent be determined by their political affiliation, legal considerations may play a role. This means in the first place that possible constitutional and statutory limitations will be addressed, adding to their significance.⁶⁹ International law is also likely to play its part in parliamentary debates. In fact, different strands of international relations research suggest a connection between the impact of international law, including international law on the use of force, and parliamentary involvement in this matter. More specifically, theories of democratic peace and scholarship on the domestic impact of international norms suggest that parliamentary involvement in military deployment decisions goes hand in hand with recourse to international legal arguments.

First of all, research that builds on liberal theories of democratic peace suggests that international legal considerations will have greater bearing on military deployment decisions if parliaments are involved in the decision-making process. In line with the central proposition of democratic peace theory that democracies do not fight each other in interstate wars, liberal international relations theorists have argued that “liberal democracies are more likely to ‘do law’ with one another.”⁷⁰ Gaubatz, for example, argues that the distinctive domestic institutions and preferences of democracies enhance the strength of their international commitments.⁷¹ Given that “respect for law is a critical component of democratic political culture,” respect for international legal rules will also have “at least significant rhetorical appeal in democratic polities.”⁷² This is confirmed by a recent study of Kreps and Wallace, which shows that the inconsistency of drone warfare with international legal principles had a negative impact on public support for drone strikes.⁷³

Taubman agrees that democratic publics prefer their governments to keep their treaty promises, and claims that this results in “a generalized commitment to international law and international institutions” because democratic structures give voice to domestic opposition and ensure that leaders remain accountable to public opinion.⁷⁴ This corresponds to the assumption of the structural model of democratic peace that the domestic institutions of established democracies are crucial for linking public attitudes to foreign policy.⁷⁵ Recent work on “parliamentary peace” suggests that parliamentary involvement in military deployment decisions is a particularly important determinant in this regard.⁷⁶ More specifically, parliamentary debates open up “intra-governmental decision-making to public scrutiny” and force “governments to give reasons for political decisions complying with the fundamental norms of the society and the identity of the nation.”⁷⁷ In consequence, national parliaments can be expected to have a decisive role in linking the popular preference for respect for international law with actual compliance with international legal rules.

Second, and in line with the latter expectation, research on the impact of norms in international politics suggests that a state’s domestic political structure is an important determinant for compliance with international norms.⁷⁸ Domestic institutions determine which actors have access to decision-making processes and, hereby, how norms are empowered domestically. If domestic institutions, like parliaments, open up decision-making to societal actors, elites are expected to be faced with “pressure from below” to comply with international norms.⁷⁹ Likewise, Cortell and Davis expect executives to “appeal to international norms in an effort to further their own preferred strategy or to block those of other officials” if “decision making is dispersed across several functionally differentiated arms of the government.”⁸⁰ In a case study of the impact of the collective security norm on the US response to Iraq’s invasion of Kuwait, Cortell and Davis describe how the involvement of parliaments in military deployment decisions enhance compliance with international norms.⁸¹

To sum up, theories of democratic peace and literature on international norms suggest a link between the impact of international legal rules on military deployment decisions and parliamentary involvement in this matter. Indeed, the dialogue between the executive and legislative branch can be expected to create another channel where (national and international) legal arguments are exchanged as a form of justificatory discourse. Even if the arguments made will not of course be exclusively, or necessarily primordially, legal in nature, and even if it is not excluded that this discourse may, at times, amount to little more than an exercise in semantics,⁸² or a dialogue des sourds, the reference to the international legal framework governing interstate recourse to force (the so-called jus ad bellum) potentially adds to what Harold Koh has called the legal and political “internalization”⁸³ of these norms at the domestic level.⁸⁴ These forms of internalization contribute to the compliance pull of the jus ad bellum by urging executive organs to provide an adequate justification for their actions at the domestic level, including in terms of conformity with international law. The importance of this justificatory discourse is all the greater when, for whatever reason, no similar debate takes place at the international level, in particular when no meaningful exchange of legal arguments takes place within the UN Security Council.⁸⁵

Evidence over the past 15 to 20 years corroborates the suggestion that “[p]arliaments and public opinion are increasingly concerned to connect constitutional decisions on war powers with the international legal appraisal of a military commitment.”⁸⁶ By way of illustration, in relation to the discussions within the German parliament on the possible participation of German forces in NATO’s Operation Allied Force, Simma observed that “the international legal issues involved were discussed at great length and in considerable depth. The respect for UN Charter law demonstrated throughout the debates was remarkable.”⁸⁷ The 1999 NATO intervention in the Federal Republic of Yugoslavia and the 2003 Iraq intervention also inspired other parliamentary assemblies to have a closer look at questions of international law.⁸⁸ The Foreign Affairs Committee of the UK House of Commons undertook an in-depth study of the alleged right of unilateral humanitarian intervention (absent Security Council authorization) in 2000.⁸⁹ The Standing Committee on Foreign Affairs of the Canadian Senate concluded that the lack of UN authorization for Operation Allied Force set an unfortunate precedent and recommended that if a permanent member were to veto a resolution authorizing military intervention in the face of grave and large-scale human rights violations, then the authority of the General Assembly should be sought on the precedent of the “Uniting for Peace” resolution.⁹⁰ In the Netherlands, the Commission of Inquiry set up after the Iraq war paid considerable attention to the compatibility of the intervention with international law.⁹¹ Again, in the course of the Chilcott inquiry in the UK, “an unprecedented amount of attention has been given to differences of views on the questions of international law involved in the matter.”⁹² In their recent volume on British war powers, Fikfak and Hooper also note a striking pervasiveness of international legal language in the dialogue between the British government and parliament, whereby the law increasingly takes center stage. In fact, the authors go as far as to express regret that the “straitjacket that law and legalistic language imposes” stifles much-needed discussion over the policy questions which parliament is constitutionally mandated to ask.⁹³

If this form of political and legal “internalization” of the jus ad bellum may contribute to its compliance pull, this does not necessarily imply that international legal considerations will ultimately prevail and that breaches of the UN Charter framework will necessarily be avoided. Several British scholars have, for instance, suggested that an inverse proportional relationship exists between the clarity of the international legal basis for military intervention (e.g. in the form of an explicit UNSC authorization) and the UK Government’s inclination to seek parliamentary support, implying that the risk that parliamentary involvement is seen as a mechanism to sidestep the UN framework and facilitate unilateralism.⁹⁴ It is obvious that national parliaments have not shied away at times from endorsing military interventions that were of dubious legality and/or that have been denounced as unlawful by many states and by a clear majority of legal opinion,⁹⁵ or from confining themselves to a “rubber stamp” type of endorsement.⁹⁶ The relationship between both branches is also marked by an endemic asymmetry in terms of access to sensitive information,⁹⁷ and, possibly, in terms of relevant legal expertise, which weakens the position of the lawmakers. International legal considerations may also retreat in the background when a nation rallies together after having been the victim of a heinous terrorist attack (whether in Paris, in Sousse, or in Istanbul).⁹⁸ It follows that increased parliamentary scrutiny is no guarantee for strict compliance with the jus ad bellum. It is moreover recalled that often the “trigger” of parliamentary war powers does not coincide exactly with the scope of application of the jus ad bellum (seeAppendix 1). In particular, minor cross-border uses of force, while nonetheless caught by article 2(4) of the UN Charter, may not require any consultation with, or approval by, the national parliament concerned. Interestingly, however, in one of the rare direct studies on the use of international law in parliamentary debates, focusing on the debates in the Spanish Congreso de los Diputados regarding the 1999 NATO intervention in the Federal Republic of Yugoslavia and the 2003 Iraq war, Marrero Rocha confirms that, even if the arguments and voting behavior of members of parliament are largely guided by partisan interests, international law may provide a useful mechanism to control governments’ external policy.⁹⁹ Still, the impact of international law arguments on the decision-making process cannot be taken for granted and merits further research.

5. International legal considerations in parliamentary debates on the coalition against IS: Tentative observations

As with previous military deployments, in numerous democratic states the inter-branch dialogue with regard to Operation Inherent Resolve has compelled governments to frame their actions in light of the normative framework of the jus ad bellum and has led the international legality of the operations to be scrutinized in national parliaments. In the Netherlands, for example, the government expressly communicated to parliament two information memorandums, spelling out, among other things, the international legal basis for the operations, and also forwarded to parliament the legal advice of an external advisor.¹⁰⁰ In Germany, the Research and Documentation Services of the Bundestag prepared an updated briefing paper ahead of the vote early December 2015, elaborating in detail on the legal context.¹⁰¹ Similar briefing papers were prepared within the UK House of Commons.¹⁰² Furthermore, following the British strike of August 21, 2015 against an IS target in Syria, leading to the death of British nationals¹⁰³ who were allegedly “actively engaged in planning and directing imminent armed attacks against the United Kingdom,”¹⁰⁴ the Joint Committee on Human Rights of the British Parliament launched an inquiry into the government’s policy on the use of drones for targeted killing.¹⁰⁵ The Joint Committee obtained oral and written evidence from various sources, including from several established international lawyers. The government for its part submitted a four-page memo, focusing primarily on the legality of the air strike under the right of self-defense.¹⁰⁶ International law considerations also surfaced in the parliamentary debates inter alia in the Netherlands,¹⁰⁷ Germany,¹⁰⁸ Canada,¹⁰⁹ Belgium,¹¹⁰ France,¹¹¹ and the United Kingdom.¹¹² Overall, the recourse to international legal arguments in the dialogues between the executive and legislative branches vis-à-vis military operations against IS thus fits in a broader trend and holds the potential of contributing to the relevance of international law as a yardstick to influence and/or assess state conduct. While an in-depth analysis is beyond the purview of this article, a few cursory comments can be made.

As a preliminary remark, it can be noted that a review of the parliamentary debates on the fight against the so-called Islamic State in the abovementioned countries shows that opposition to military involvement was led by left-wing parties, relying forcefully upon legal arguments.¹¹³ This was undoubtedly the case for opposition parties in Canada (New Democratic Party, Green Party, Liberal Party¹¹⁴), Belgium (Ecolo-Groen!, sp.a, and PVDA¹¹⁵), and the United Kingdom (Labour¹¹⁶ and SNP¹¹⁷). However, even in the other three states where left-wing parties were part of the governing coalition, or even in charge thereof, these parties were noticeably more hesitant (e.g. the Netherlands¹¹⁸) or received significant pushback from even further left-leaning parties (e.g. Germany—Die Linke and Bündnis 90/Die Grünen¹¹⁹; France—Gauche Démocrate et Républicain¹²⁰). Although it might be said that “the duty of the opposition is to oppose,”¹²¹ it seems that left-wing parties thus generally maintained a more principled pacifist (and, in casu, legalist) stance, regardless of their particular role.¹²²

If legal arguments surfaced in the debates over the coalition against IS in various national parliaments, they do not necessarily seem to have played a central role. The reliance on arguments drawn from international law varies from one parliament to another. Thus, it would appear that international law concerns received considerable attention in the debates before the Dutch Tweede Kamer der Staten-Generaal, the Belgian Chambre des Représentants, the British House of Commons, and the German Bundestag, but perhaps less so before the French and Canadian parliaments. They were hardly discussed at all in the Australian parliament, which is ostensibly related in part to the fact that—contrary to the other legislative bodies—it was not formally consulted by the executive branch. The legal aspect may be particularly prominent when decisions to deploy the armed forces are additionally subject to judicial scrutiny, as is the case in Germany. Otherwise, a legislative body’s sensitivity to considerations of international law may vary, depending, for example, on the particular model of parliamentary democracy (is it a genuine liberal democracy or rather a pseudo-democracy where critics of military intervention risk being side-lined? Coalition government or other? What is the importance of party loyalty?¹²³) and the domestic political context.¹²⁴ Another factor pertains to the legal expertise present within a parliamentary body. Indeed, when presented with a highly technical legal argument, many parliamentarians may feel ill-placed to scrutinize the legal validity of the executive’s actions.¹²⁵ In such context, the presence of established (international) lawyers arguably increases the likelihood that questions of international law will be addressed.¹²⁶

On a different note, an analysis of the debates reveals that the international legal mandate received less attention in the parliamentary debates pertaining to operations on Iraqi soil, as opposed to debates pertaining to the extension of operations to IS targets within Syrian territory. This appears to be linked to the fact that the legal basis for the former operations was rather uncontroversial, whereas the opposite was true for operations on Syrian territory.¹²⁷ Indeed, inasmuch as coalition operations in Iraq were consented to by the internationally recognized government in Baghdad,¹²⁸ this was widely regarded as a sufficient legal basis.¹²⁹ By contrast, absent similar consent from Damascus for coalition operations on Syrian territory, the legality of those operations was (and still remains) far more contested among international legal scholars¹³⁰—views indeed differ depending on whether authors opt for a more conservative/traditional reading of the right of self-defense as per the case law of the International Court of Justice (in essence requiring some degree of state involvement for attacks by non-state armed groups to trigger the right of self-defense), or rather a more flexible interpretation along the lines of the so-called “unable or unwilling” doctrine.¹³¹ The latter legal controversy also filtered into the parliamentary debates. Thus, during the debate in the Belgian Chambre des Représentants, several MPs referred to contradicting legal scholarship on the unwilling/unable doctrine, thereby undermining the strength of the legal argument espoused (primarily) by the opposition. Moreover, whereas some relied on scholarship, others pointed to case law of the International Court of Justice to make their case. ¹³²

Perhaps even more determinative for the impact of international legal considerations than the strength of pacifist parties or the controversial nature of the legal justification put forward by the executive is the presence of an authoritative legal opinion, with the potential of nipping much of the legal argument in the bud. For example, the Dutch parliamentarian debate regarding the legal basis for operations in Syria seemed by and far settled after the publication of a legal opinion by a highly regarded expert—commissioned by the government—in June 2015 (or perhaps already since September 2014, when the first opinion by the expert was shared with MPs).¹³³ This is exemplified by one MP’s statement, who observed that the proposed mission “corresponds seamlessly” to the expert opinion.¹³⁴ Similarly, the governing coalition’s interventions in the German Bundestag frequently referred to the legal opinion published by the latter’s Research and Documentation Services to shield against opposing legal arguments. The Foreign Minister himself claimed that the report had “confirmed the constitutionality and legitimacy under international law of the Bundeswehr’s overseas deployment,” which would “hopefully help to clarify the open questions discussed here as well as the legal aspects of the debate.”¹³⁵ British MPs also seemed reassured by the Attorney General’s consenting opinion to the government’s motion¹³⁶ and briefings prepared by the House of Commons Library.¹³⁷ And, on the contrary, because such an authoritative “national” report was not present in Belgium, the level of debate pertaining to the correct legal point of view appears to have soared.¹³⁸ Although it is to be applauded that governments frame their actions in light of the international law by appealing to expert legal opinions, it is somewhat worrisome if and when these opinions on the legality of the use of military force are accepted as infallible, even in cases—like the example of coalition operations on Syrian soil—where the voiced opinion is controversial at the very least. This is a fortiori the case where the opinion stems not from an external legal expert but rather from government legal advisors, who—as the UK’s Chilcott Inquiry has amply shown—may be under considerable internal political pressure when preparing their advice.¹³⁹

At times, parliamentary debates suggest that international law is given considerable weight and/or offers a rallying point for the opposition. Especially in the case of the prohibition on the use of force, its explicit invocation in the policy debate can question or delegitimize “alternative choices” and raise the “burden of justification” for the government’s proposal.¹⁴⁰ Thus, in the Canadian House of Commons, several MPs criticized the absence of a report to the UN Security Council by the government in accordance with article 51 of the UN Charter (which was eventually submitted a few days later) and criticized the government’s disregard of international law.¹⁴¹ And in the Dutch parliament, several MPs as well as the Prime Minister initially took the view that no military operations ought to be undertaken in Syrian territory given that the conditions for a clear international legal mandate had not (yet) been met.¹⁴² In the debate in the UK House of Commons in the summer of 2013, opposition leader Edward Milliband asserted that “[t]he UN is not some inconvenient sideshow and we do not want to engineer a ‘moment.’ Instead, we want to adhere to the principles of international law.”¹⁴³ A Belgian MP also railed against the country’s envisaged involvement in Syria, which he considered to clash with the principled stance of every Belgian government since World War II to respect and promote international law.¹⁴⁴ The German opposition to military action in Syria also pointed out that not abiding by international law now would render hollow future calls to respect it.¹⁴⁵ Finally, the UK Joint Committee on Human Rights also commented that the “UK’s compliance with its international treaty obligations sends an important message to the rest of the world about the importance of abiding by international obligations: if the UK appears to be selective in its approach to its international obligations, that would be rapidly seized upon and invoked by other States as an excuse for their record of disrespect for international law.” Interestingly, the Committee went on to stress that the “importance internationally of the UK being seen to comply with its international obligations is a point which has been forcefully made by a number of significant visitors to the UK.”¹⁴⁶

At the same time, several counter-examples can be cited. The criticism that the Canadian government perceived of the legal justification of the operation as an “afterthought,” as argued by some,¹⁴⁷ for instance, cuts both ways. On several occasions, members of parliament moreover fulminated against a strict reliance on the black-letter law, bordering on outright derision for such arguments. Again in the Canadian House of Commons, (then) Prime Minister Harper, for example, mockingly refuted the idea of “lawyers from ISIL taking the Government of Canada to court and winning.”¹⁴⁸ In the Bundestag, some members insisted that, article 51 of the UN Charter notwithstanding, international law was “no suicide pact” and that they were “not in a seminar,” with some appealing to the opposition to “put aside . . . from lecturing in a filibuster-like fashion, nitty-gritty, and seminar-style on a differentiated analysis of the legal question.”¹⁴⁹ In the Netherlands, one opposition member denounced the “cowardice” of hiding behind the lack of an international legal mandate,¹⁵⁰ whereas others introduced the—pointedly derogatory—term “international law fetishism.”¹⁵¹ Meanwhile in Belgium, a parliamentarian of the ruling coalition accused opposition members of “protecting IS against the bombing by our F16s,”¹⁵² seemingly echoing accusations by British government officials warning against siding with “terrorist sympathisers” ahead of the parliamentary vote.¹⁵³ A mixed picture thus emerges.

Arguably, increased parliamentary (and judicial) oversight of the executive’s “war powers” may also have a peculiar side effect in that the focus of the legal debate may gradually shift from the international legal perspective to a domestic/constitutional perspective. By way of illustration, when parliaments conditionally approve the deployment of the armed forces in a given operation, subsequent scrutiny may focus more on the compliance of the executive with those conditions (ratione temporis, etc.) imposed by parliament, rather than with the intrinsic validity of the action under international law proper. This is to some extent what has happened in the United States. It is telling, for example, that the speech by the US Department of Defense General Counsel Stephen Preston at the annual meeting of the American Society of International Law in 2015,¹⁵⁴ one of several high-level speeches explaining the US government’s position on the use of military force after 9/11, focused primarily on the compatibility of the government’s actions, including the military operations against IS, with the existing AUMF resolutions adopted by Congress in 2001 and 2002,¹⁵⁵ rather than with its compatibility with international law. While other, similar high-level speeches by key officials have been more deferential to both domestic and international law,¹⁵⁶ debates within US Congress again appear to have focused exclusively on the scope of the 2001 AUMF—specifically on whether that resolution contains a blanket authorization for military operations against IS. By contrast, one is hard pressed to find even a single reference to the UN Charter, or to international law, in the relevant records of the Senate Foreign Relations Committee, the Senate Armed Services Committee, the House Foreign Affairs Committee, or the House Armed Services Committee.¹⁵⁷ In the dialogue between the executive and the legislative branch, specific attention was paid to the notion of “associated persons or forces,” a concept which is key to the executive branch’s understanding of the 2001 AUMF resolution,¹⁵⁸ but which is unknown to the jus ad bellum.¹⁵⁹ The use of such specific terms and conditions may in turn infect the justificatory discourse at the international level and result in a certain cross-pollination between the international and domestic legal debate, leading governments to adapt their international legal arguments to better fit with the domestic legal framework.

In the end, while the evidence is not completely unequivocal, an examination of parliamentary debates on the authorization of the use of force as part of the US-led coalition against IS generally tends to support the view that increased parliamentary involvement in the executive’s war powers contributes to the relevance of the jus ad bellum as a discursive tool. It is not unlikely that this awareness of international legal concerns will further gain traction pursuant to the activation in July 2018 of the International Criminal Court’s jurisdiction over the crime of aggression pursuant to article 8bis of the Rome Statute.¹⁶⁰ The prospect (if only remote) of political and military leaders being held criminally accountable for military interventions abroad—as opposed to the sole risk of state responsibility—may indeed result in greater attention for jus ad bellum considerations in the domestic decision-making process. As Dinstein puts it: “Only if it dawns upon the actual decision-makers that—when they carry their country along the path of war in contravention of international law—they expose themselves to individual criminal accountability, are they likely to hesitate before taking the fateful step.”¹⁶¹ As such, especially for those countries where formal parliamentary war powers remain limited or inexistent, the recent activation of the ICC’s jurisdiction in respect to crimes of aggression may provide a good opportunity to reconsider the role of the legislative branch with respect to foreign troop deployments, and, possibly, to provide for proper democratic oversight in respect of any “use of armed force”—thus aligning the trigger of parliamentary war powers to the UN Charter (article 2(4)) and the Rome Statute (article 8bis).

Appendix 1: Comparative overview parliamentary involvement military deployments

Country	Legal basis	Parliamentary powers in a nutshell	(Formal) exceptions	Parliamentary involvement in Operation Inherent Resolve
Australia	N/A	Troop deployments are part of the executive’s prerogative. Parliament does not have any formal war powers. Nor has any unwritten convention emerged as of yet obliging the executive branch to consult with parliament.	N/A	No formal consultation of parliament in respect of the initial deployment in Iraq (2014) or the expansion of operations to Syria (2015)
Belgium	Article 167(1) of the Belgian Constitution	The decision to send armed forces abroad is exclusively in the hands of the executive. The government is only obliged to inform parliament ex post of “the state of war.”Note: The Belgian parliament was asked for authorization prior to the military interventions in Libya (2011) and Iraq (2014), when Belgium was governed by a caretaker government. However, with respect to the involvement in Syria in 2016, the successor government has stressed that no legal requirement exists to seek parliamentary approval.	N/A	Deployment in Iraq (2014): caretaker government sought and obtained ex ante authorization from the Chambre des Représentants.Additional deployment in Syria (2016): government decision to deploy was later approved in a resolution of the Chambre des Représentants.
Canada	N/A	Troop deployments are part of the executive’s prerogative. Since 2006, the Canadian government consistently held votes to secure parliamentary approval for combat missions. However, the parliament’s role remains ambiguous and future governments may reaffirm the executive’s full discretion over military deployments.	N/A	Both the initial deployment in Iraq (2014) and the subsequent expansion of operations to Syria (2015) were approved by the House of Commons.
Denmark	Section 19(2) of the Danish Constitution	The consent of the Folketing is required for the “use of military force against any foreign state.”	Prior consent of the Folketing is not required when the armed forces are deployed to defend against an armed attack upon Denmark or Danish forces. In such scenario, the action undertaken must be submitted to parliament immediately afterwards.	Both the initial deployment in Iraq (2014) and the subsequent expansion of operations to Syria (2016) were approved by the Folketing.
France	Article 35 of the French Constitution	The decision to send armed forces abroad rests with the executive branch. The government nonetheless has to inform parliament about decisions to deploy armed forces abroad within three days. If a troop deployment exceeds a period of four months, parliamentary authorization is required to prolong the military operation.	N/A	Deployment in Iraq (2014): the Assemblée nationale was informed by the government following the deployment of the armed forces; the prolongation of the operation beyond four months was formally approved by the Assemblée.Deployment in Syria (2015): idem
Germany	2005 Parliamentary Participation Act (Parlamentsbeteiligungsgesetz)Note: already in1994, the Bundesverfassungsgericht held that deployment of the German armed forces in armed operations must be approved by the Bundestag	Section 2 of the first paragraph of the Parliamentary Participation Act states that the deployment of armed forces abroad requires parliamentary consent. The Parliamentary Participation Act defines the “deployment of armed forces” as “involvement, or anticipated involvement, of the Federal Armed Forces personnel in armed operations” abroad.	The Parliamentary Participation Act excludes preparatory and planning measures from the requirement of prior parliamentary consent. The same applies to humanitarian relief or support operations in which arms are only carried for the purposes of self-defense, if the soldiers are not expected to get involved in armed operations.	Deployment of armed forces in Iraq (early 2015) and Syria (late 2015) were both formally authorized by the Bundestag.
Netherlands	Article 100 of the Dutch Constitution	The government has to inform the parliament ex ante whenever it intends to deploy the armed forces “for the maintenance or promotion of the international legal order” (article 100(1)).Note: if parliament disagrees with a government decision to deploy armed forces abroad, this can result in a no-confidence vote which terminates the governing coalition. This is what happened in 2010, when the Dutch government fell over the extension of its participation in the ISAF operation in Afghanistan.	Article 100(2) of the Constitution clarifies the obligation to inform Parliament does not apply when there are “compelling reasons” that prevent the ex ante sharing of information. In such scenario, information must be provided “as soon as possible.”In addition, in light of the phrasing of article 100(1) it is argued that the obligation does not apply for self-defense operations.More controversially, it has been argued that the obligation to inform parliament only applies to “voluntary” troop deployments, but not to deployments pursuant to treaty obligations (such as article 5 of the NATO Treaty).	The government informed the parliament by means of a so-called article 100 letter both in respect to the initial deployment in Iraq (2014) as well as with regard to the expansion of operations to Syria (2016).
United Kingdom	Unwritten convention	While there is no statutory obligation, as a result of recent practice (including the government’s defeat over military action in Syria in August 2013) an unwritten “convention” has emerged according to which the House of Commons must have an opportunity to debate the matter before British armed forces are deployed in offensive military operations. This has resulted in an “informal veto” on the part of the British parliament.	The convention does not apply when there is an emergency situation (see, e.g., 2011 UK Cabinet Manual, para. 5.38).	Both the initial deployment of British forces in Iraq (2014) and the subsequent expansion of operations to Syria (2015) were approved in separate resolutions of the House of Commons.
United States	US Constitution and 1973 War Powers resolution(Note: subsequent presidential administrations have contested, or at least refrained from confirming, the constitutionality of the resolution.	The war powers resolution applies to every introduction of the US Armed Forces into hostilities, or into situations where imminent hostilities is clearly indicated by the circumstances.The resolution requires ex ante consultation with Congress prior to deployment “in every possible instance.” In addition, the US President must report to Congress within 48 hours following the deployment of US armed forces abroad, and must subsequently report at least on a six-monthly basis.	Section 5(b) of the War Powers resolution makes exception for the situation where Congress “is physically unable to meet as a result of an armed attack upon the United States.”	The executive branch has claimed that the 2001 AUMF (Authorization on the Use of Military Force) resolution, provides implicit statutory authority for military operations against IS in Iraq and Syria (2014–). In spite hereof, the Obama administration has proposed a new resolution expressly authorizing the use of military force against IS. In light of political opposition, however, the proposal was not taken further in Congress. Discussions within Congress as to a modification and/or repeal of the 2001 AUMF remain ongoing.
		Deployments beyond a period of 60 days, or, exceptionally 90 days, must be authorized by Congress.The competence to “declare war” is moreover reserved to Congress pursuant to the US Constitution

Sources (other than the primary instruments themselves): Dirk Peters & Wolfgang Wagner, Between Military Efficiency and Democratic Legitimacy: Mapping Parliamentary War Powers in Contemporary Democracies, 1989–2004, 64 Parliamentary Aff. 175–192 (2010); for European countries: Eiko Biehl, Bastian Giegerich, & Alexandra Jonas, Strategic Cultures in Europe (2013); Sandra Dieterich, Hartwig Hummel, & Stefan Marschall, Parliamentary War Powers: A Survey of 25 European Parliaments (2010); for Australia: Phil Larkin & John Uhr, Bipartisanship and Bicameralism in Australia’s “War on Terror”: Forcing Limits on the Extension of Executive Power, 15 J. Legis. Stud. 239 (2009); for Belgium: Yf. Reykers & Daan Fonck, Who Is Controlling Whom? An Analysis of the Belgian Federal Parliament’s Executive Oversight Capacities towards the Military Interventions in Libya (2011) and Iraq (2014–2015),’ 68 Studia Diplomatica 91 (2016); Tom Ruys Parlementaire Controle op Het Inzetten Van Strijdkrachten in Het Buitenland, 10 Rechtskundig Weekblad (2009); for Canada and the UK: Philippe Lagassé, Parliament and the War Prerogative in the United Kingdom and Canada: Explaining Variations in Institutional Change and Legislative Control, 70 Parliamentary Aff. 280 (2017); for Canada: Norman Hillmer & Philippe Lagassé, Parliament Will Decide: An Interplay of Politics and Principle, 71 Int’l J. 328 (2016); for France: Falk Ostermann, France’s Reluctant Parliamentarisation of Military Deployments: The 2008 Constitutional Reform in Practice, 40 W. Eur. Pol. 101 (2017); For the UK: Patrick Mello Curbing the Royal Prerogative to Use Military Force: The British House of Commons and the Conflicts in Libya and Syria, 40 W. Eur. Pol. 80 (2017).

Footnotes

1

Letter dated September 20, 2014, from the Permanent Representative of Iraq to the United Nations addressed to the President of the Security Council (Sept. 22, 2014), U.N. Doc. S/2014/691.

2

Further, see Tom Ruys & Nele Verlinden, Digest of State Practice: 1 July–31 December 2014, 2 J. Use of Force & Int’l L. 119, 131–145 (2015).

3

For more information, see the webpage of the Global Coalition against IS, available athttp://theglobalcoalition.org/en/home/.

4

Id. French air raids in Iraq (as of September 2014) and Syria (as of September 2015) were stepped up in particular in November 2015, following the terrorist attacks in Paris. Following his election late 2015, Prime Minister Justin Trudeau put an end to Canadian air strike operations in Iraq and Syria early 2016. Canada nonetheless continued to participate in Operation Inherent Resolve, i.e. through reconnaissance missions and refueling sorties. See, e.g., http://www.forces.gc.ca/en/operations-abroad-current/op-impact.page.

5

See Tom Ruys, Nele Verlinden, & Luca Ferro, Digest of State Practice: 1 January–30 June 2015, 2 J. Use of Force & Int’l L. 257, 279–283 (2015) [hereinafter Ruys et al., Digest of State Practice: 1 January (2015)]; Tom Ruys, Luca Ferro, & Nele Verlinden, Digest of State Practice: 1 July–31 December 2015, 3 J. Use of Force & Int’l L. 126, 145–156 (2016) [hereinafter Ruys et al., Digest of State Practice: 1 July (2016)]; Tom Ruys, Luca Ferro, & Nele Verlinden, Digest of State Practice: 1 January–30 June 2016, 3 J. Use of Force & Int’l L.290, 303–306 (2016) [hereinafter Digest of State Practice: 1 January (2016)]; Tom Ruys, Luca Ferro, Nele Verlinden, & Carl Vander Maelen, Digest of State Practice: 1 July–31 December 2016, 4 J. Use of Force & Int’l L. 161, 179–185 (2017) [hereinafter Ruys et al., Digest of State Practice: 1 July (2017)].

6

On the various modalities of “involvement”, see infra, section 3.

7

See Shaun Walker, Russian Parliament Grants Vladimir Putin Right to Deploy Military in Syria, The Guardian, Sept. 30, 2015, http://www.theguardian.com/world/2015/sep/30/russian-parliament-grants-vladimir-putin-right-to-deploy-military-in-syria; Fionnuala Ní Aoláin, Authorizing Force: A Review of Turkish, Dutch and French Action, Just Security, Oct. 16, 2014, https://www.justsecurity.org/16282/authorizing-force-review-turkish-dutch-french-action/. Note: Russia is not a member of the US-led coalition but has been deploying troops in Syria, with the consent of the Syrian government in Damascus, since September–October 2015. See Tom Ruys, Luca Ferro, & Nele Verlinden, Digest of State Practice: 1 July–31 December 2015, J. Use of Force & Int’l L. 154–156 (2016). Turkey was initially active in Syria on an autonomous basis but joined Operation Inherent Resolve in the summer of 2015. Id. at 141–142.

8

According to article 2(4) UN Charter, “[a]ll Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.”

9

Case Concerning Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States), I.C.J. Reports 14, para. 246 (June 27, 1986).

10

Seehttp://democracyranking.org/wordpress/. This excludes countries such as Turkey, or the Arab and North African members of the US-led coalition. The same result emerges when the analysis is limited to “full” or “flawed” democracies in the sense of the Democracy Index of the Economist Intelligence Unit. Seehttps://www.eiu.com/topic/democracy-index.

11

Since the parliamentary records of the Danish Parliament, or Folketing, are only available in Danish (http://www.ft.dk/), the authors have been unable to directly examine the parliamentary debates in Denmark in respect of Operation Inherent Resolve.

12

Lori Damrosch, Is There a General Trend in Constitutional Democracies Toward Parliamentary Control over War-and-Peace Decisions?, 90 ASIL Proceedings 36, 36 (1996) [hereinafter Damrosch, Control over War-and-Peace Decisions]. In a similar vein, see Lori Damrosch, Democratization of Foreign Policy and International Law, 1914–2014, 21 ILSA J. Int’l & Comp. L. 281, 287–288 (2014) [hereinafter Damrosch, Democratization].

13

As is well-known, in the United States, subsequent presidents have contested, or at least refrained from confirming, the constitutionality of the US Congress’s so-called War Powers Resolution (Joint Res. concerning the War Powers of Congress and the President, 50 U.S.C. 1541–1548, H.R.J. Res. 542, 93rd Cong., Pub. L. No. 93–148, 87 Stat. 555 (Nov. 7, 1973)). E.g., Rebecca Ingber, Co-Belligerency, 42 Yale J. Int’l L. 67, 74 n. 20, 76 n. 25.

14

See, e.g., Lori Damrosch, The Interface of National Constitutional Systems with International Law and Institutions on Using Military Forces: Changing Trends in Executive and Legislative Powers, inDemocratic Accountability and the Use of Force in International Law 50 (Charlotte Ku & Harold Jacobson eds., 2003); Michael Bothe & Andreas Fischer-Lescano, The Dimensions of Domestic Constitutional and Statutory Limits on the Use of Military Force, inRedefining Sovereignty: The Use of Force after the Cold War 203 (Michael Bothe, Mary Ellen O’Connell, & Natalino Ronzitti eds., 2005).

15

Damrosch, Control over War-and-Peace Decisions, supra note 12, at 37–38.

16

Damrosch, supra note 14, at 55–56.

17

Wolfgang Wagner, Dirk Peters, & Cosima Glahn, Parliamentary War Powers around the World, 1989–2004: A New Dataset (DFAC Occasional Papers no. 25). Geneva: Geneva Centre for the Democratic Control of Armed Forces.

18

A new article 100 was inserted into the Dutch Constitution. See The Netherlands, Raad van State, Rijkswet van 22 juni tot verandering in de Grondwet van de bepalingen inzake de verdediging, 22 juni 2000, Staatsblad van het Koninkrijk der Nederlanden, Jaargang 2000, 294.

19

Spain, Jefatura del Estado, Ley Orgánica 5/2005, de 17 de noviembre, de la Defensa Nacional, November 18, 2005, BOE núm. 276, 37717, art. 17(1). If urgent reasons prevent prior consultation, then the government is required to have the Congreso sanction the deployment as soon as possible (art. 17(2)).

20

Germany, Judgment of the BVerfG of July 12, 1994, translated in 106 I.L.R. 1, 320 (1994).

21

Germany, Bundestag, Gesetz über die parlamentarische Beteiligung bei der Entscheidung bewaffneter Streitkräfte im Ausland, March 18, 2005, 1 Bundesgesetzblatt 775.

22

See, e.g., Germany, Judgment of the BVerfG of May 7, 2008, 2 BvE 1/03, Absatz-Nr. (1–92) (finding that the engagement of German AWACS aircraft in NATO operation Display Deterrence, established to protect Turkey in the face of the US-British intervention in Iraq, should have been authorized by Parliament; remark: the events under consideration preceded the entry into force of the 2005 Parliamentary Authorization Act); Germany, Judgment of the BVerfG of September 23, 2015, 2 BvE 6/11, Absatz-Nr. (1–125) (finding that the government was not obliged to retrospectively seek the Bundestag’s approval of the completed evacuation of German citizens from Libya early 2011).

23

France, Congrès, Loi constitutionelle No. 2008–724 de modernisation des institutions de la Ve République, July 24, 2008, Journal Officiel de la République Française, NOR: JUSX0807076L (amending article 35 of the French Constitution of September 28, 1958).

24

Philippe Lagassé, Parliament and the War Prerogative in the United Kingdom and Canada: Explaining Variations in Institutional Change and Legislative Control, 70 Parliamentary Aff. 280, 280 (2017).

25

See United Kingdom, House of Lords and House of Commons–Joint Committee on the Draft Constitutional Renewal Bill, Draft Constitutional Renewal Bill. Volume I: Report, July 31, 2008, http://www.publications.parliament.uk/pa/jt200708/jtselect/jtconren/166/166.pdf.

26

United Kingdom, Cabinet Office, The Cabinet Manual, October 2011, para. 5.38, https://www.gov.uk/government/publications/cabinet-manual. Further, Claire Mills, Parliamentary Approval for Deploying the Armed Forces: An Update, Oct. 13, 2014, UK House of Commons Briefing Paper CBP-7166, http://researchbriefings.parliament.uk/ResearchBriefing/Summary/CBP-7166#fullreport.

27

Ingber, supra note 13, at 74.

28

See, e.g., Heiner Hänggi, The Use of Force under International Auspices: Parliamentary Accountability and “Democratic Deficits”, inThe “Double Democratic Deficit”: Parliamentary Accountability and the Use of Force under International Auspices 13 (Hans Born & Heiner Hänggi eds., 2004).

29

Damrosch, supra note 14, at 40; Louis Henkin, How Nations Behave: Law and Foreign Policy 64 (2d ed. 1979).

30

Damrosch, Democratization, supra note 12, at 288, 292.

31

See, e.g., The Netherlands, Commissie van Onderzoek Besluitvorming Irak, Rapport (2010), also available athttps://www.rijksoverheid.nl/documenten/rapporten/2010/01/12/rapport-commissie-davids. See also on the UK’s Iraq Inquiry (or “Chilcott Inquiry”): http://www.iraqinquiry.org.uk/, in particular section 3.8, “Development of UK Strategy and Options, 8 to 20 March 2003,” on parliamentary approval for military action (at 559–571) and section 5, “Advice on the Legal Basis for Military Action, November 2002 to March 2003,” on the debate as to the legality of the operation.

32

See § 5(b) of the War Powers resolution. Sections 2 and 4, moreover, contain a duty of prior (“in every possible instance”) and periodic consultation with Congress (within 48 hours of the launch of an operation and subsequently once every six months). But see supra note 13.

33

See Lagassé, supra note 24, at 296 (observing that the trend has been more “ambiguous” than in the UK).

34

In the jus ad/contra bellum (international law on the use of force), what matters is the occurrence of a “use of force,” or—for purposes of ascertaining the application of the right of self-defense—an “armed attack.” With the adoption of the UN Charter, the former concepts replaced the language of “war” that is still in use in the 1928 Kellogg-Briand Pact. In the jus in bello (law of armed conflict), the language of war was replaced by that of “armed conflict” as a result of the 1949 Geneva Conventions.

35

See, e.g., German Parliamentary Participation Act § 2 [Ein Einsatz bewaffneter Streitkräfte liegt vor, wenn Soldatinnen oder Soldaten der Bundeswehr in bewaffnete Unternehmungen einbezogen sind oder eine Einbeziehung in eine bewaffnete Unternehmung zu erwarten ist]. On Canada and the UK, see, e.g., Lagassé, supra note 24, at 289, 294.

36

See, for instance, Dutch Const., art. 100(2), which provides that in case urgent reasons prevent the government from informing parliament prior to the actual deployment, information must nonetheless be provided as soon as possible. The German Parliamentary Participation Act in turn envisages a system of ex post facto authorization in situations of urgency. For relevant case law of the Bundestag, see supra note 22. With regard to the UK, see 2011 UK Cabinet Manual, supra note 26, para. 5.38.

37

Ben Hubbard, Mark Mazzetti, & Mark Landler, Blasts in the Night, a Smell, and a Flood of Syrian Victims, The New York Times, Aug. 26, 2013, http://www.nytimes.com/2013/08/27/world/middleeast/blasts-in-the-night-a-smell-and-a-flood-of-syrian-victims.html.

38

Syria Crisis: Cameron Loses Commons Vote on Syria Action, BBC News, Aug. 30, 2013, http://www.bbc.com/news/uk-politics-23892783. Further, Juliet Kaarbo & Daniel Kenealy, No, Prime Minister: Explaining the House of Commons’ Vote on Intervention in Syria, 25 Eur. Security 28 (2015).

39

S. Brown & E. Kirschbaum, Germany, Britain Say Won’t Take Part in Anti-IS Air Strikes in Syria, Reuters, Sept. 11, 2014, http://www.reuters.com/article/2014/09/11/iraq-crisis-germany-britain- idUSB4N0QV00920140911.

40

Senate Foreign Relations Committee, Joint Res. to authorize the limited and specified use of the United States Armed Forces against Syria, S.J. Res., 113th Cong., 1st Sess. (Sept. 6, 2013).

41

See, e.g., United States, White House, Remarks by the President in Address to the Nation on Syria, Sept. 10, 2013, https://obamawhitehouse.archives.gov/the-press-office/2013/09/10/remarks-president-address-nation-syria.

42

E.g., Karen DeYoung & Ed O’Keefe, Senate Sets Aside Authorization Resolution, The Washington Post, Sept. 12, 2013, https://www.washingtonpost.com/world/national-security/senate-sets-aside-resolution-on-military-strike-against-syria/2013/09/11/428887bc-1b19-11e3-a628-7e6dde8f889d_story.html; Joel Achenbach, Once-Obvious Congressional Alliances Go Out the Window, The Washington Post, Sept. 11, 2013, https://www.highbeam.com/doc/1P2-35115070.html.

43

Kenneth Mayer, Executive Power in the Obama Administration and the Decision to seek Congressional Authorization for a Military Attack against Syria: Implications for Theories of Unilateral Action, 4 Utah L. Rev. 829 (2014).

44

Belgium, Chambre des Représentants, Résolution sur la Situation en Irak et la Participation de la Belgique à la Coalition Internationale contre l’EI, Sept. 26, 2014, Parl. Doc. 54, 0305/004, 3.

45

Canada, House of Commons, 41st Parl., 2d Sess., Vote No. 252, Oct. 7, 2014 (157 in favor, 134 against).

46

Canada, House of Commons, 41st Parl., 2d Sess., Vote No. 368, Mar. 30, 2015 (142 in favor, 129 against); Belgium, Chambre des Représentants, Résolution relative à l’engagement de la Défense belge contre l’État islamique (EI ou DAECH) en Irak et en Syrie, June 30, 2016, Parl. Doc. 54, 1883/006.

47

Danish Parliament Approves Air Strikes against IS in Iraq, China Daily, Oct. 2, 2014, http://www.chinadaily.com.cn/world/2014-10/02/content_18693430.htm; Denmark, Ministry of Foreign Affairs, Broad Support in the Danish Parliament Making Denmark a Frontrunner in the Fight against Da’esh, Apr. 19, 2016, http://um.dk/en/news/NewsDisplayPage/?newsID=A8B901DC-845E-4690-930F-CDF5E4B5A130.

48

United Kingdom, House of Commons, Debate, Sept. 26, 2014, Hansard Record of Commons Debate (524 in favor, 43 against); Germany, Bundestag, Annahme der Beschlussempfehlung auf Drucksache 18/3857, Jan. 29, 2015 (457 in favor, 79 against, 54 abstentions).

49

United Kingdom, House of Commons, Debate, Dec. 2, 2015, Hansard Record of Commons Debate (397 in favor, 223 against); Germany, Bundestag, Annahme der Beschlussempfehlung auf Drucksache 18/6912, Dec. 4, 2015 (445 in favor, 145 against, 7 abstentions).

50

France, Assemblée Nationale, XIVe Législature, Troisième Session Extraordinaire de 2013–2014, Première Séance, Sept. 24, 2014.

51

France, Assemblée Nationale, XIVe Législature, Vote en Application de l’Article 35, Alinéa 3, de la Constitution, Session Ordinaire de 2014–2015, January 13, 2015 (488 in favor, 1 against).

52

France, Assemblée Nationale, XIVe Législature, Deuxième Session Extraordinaire de 2014–2015, Première Séance, Sept. 15, 2015; France, Assemblée Nationale, XIVe Législature, Vote en Application de l’Article 35, Alinéa 3, de la Constitution, Session Ordinaire de 2015–2016, Nov. 25, 2015 (515 in favor, 4 against).

53

The Netherlands, Ministers van Buitenlandse Zaken, Defensie, en Buitenlandse Handel en Ontwikkelingssamenwerking, Artikel 100-brief deelneming aan internationale strijd tegen ISIS, September 24, 2014, Kamerstuk 27925 nr. 506.

54

The Netherlands, Ministers van Buitenlandse Zaken, Defensie en Buitenlandse Handel en Ontwikkelingssamenwerking, Aanvullende artikel 100-brief Nederlandse bijdrage aan de strijd tegen ISIS, Jan. 29, 2016, Kamerstuk 27925 nr. 570.

55

This argument is based on the idea that (i) the 2001 AUMF resolution authorizes the use of force against “those nations, organizations, or persons [which the President determines] planned, authorized, committed, or aided [the 9/11 attacks], or harboured such organizations or persons” (Joint Res. to Authorize the Use of United States Armed Forces against Those Responsible for the Recent Attacks Launched against the United States, S.J. Res. 23, 107th Cong., 1st Sess., Pub. L. No. 107–40, 115 Stat. 224 (Sept. 18, 2001))—a phrase which the executive branch understands as referring to al-Qaeda, the Taliban, and “associated forces,” and that (ii) IS is in a sense a “spin-off” of al-Qaeda. See, e.g., United States, White House, Report on the Legal and Policy Frameworks guiding the United States’ Use of Military Force and related National Security Operations, Dec. 2016, https://www.justsecurity.org/wp-content/uploads/2016/12/framework.Report_Final.pdf, 4ff.

56

United States, White House, Letter from the President to the Congress of the United States—Authorization for the Use of United States Armed Forces in connection with the Islamic State of Iraq and the Levant, Feb. 11, 2015, Annex, https://obamawhitehouse.archives.gov/the-press-office/2015/02/11/letter-president-authorization-use-united-states-armed-forces-connection. Further, see Ruys et al., Digest of State Practice: 1 January 2015, supra note 5, at 294–295.

57

Against the background of the impending US presidential elections, it would seem that the opposition was influenced both by concerns that a new resolution might overly tie the hands of the incoming president, as well as concerns that it might give the incoming president free reign. See, e.g., Patricia Zengerle, Senate Democrats Oppose “Blank Check” for Islamic State Fight, Reuters, March 11, 2015, http://www.reuters.com/article/us-mideast-crisis-congress-democrats-idUSKBN0M71HV20150312; Jonathan Ernst, Obama Request for Islamic State Fight Won’t Pass US House: Top Republican, Reuters, April 13, 2015, http://www.reuters.com/us-mideast-crisis-congress-idUSKBN0N41Q320150413; Charles Tiefer & Kathleen Clark, Congressional and Presidential War Powers as a Dialogue: Analysis of the Syrian and ISIS Conflicts, Washington University in St. Louis School of Law Legal Studies Research Paper No. 16-07-06 (2016), available athttp://papers.ssrn.com/sol3/papers.cfm?abstract_id=2812192.

58

Ingber, supra note 13, at 69.

59

Australia, Parliament, Parliamentary Involvement in Declaring War and Deploying Forces Overseas—Background Note, Mar. 22, 2010, https://www.aph.gov.au/binaries/library/pubs/bn/pol/parliamentaryinvolvement.pdf.

60

See, e.g., Australia House of Representatives, 1st Sess., 4th Period, Sept. 3, 2014, Official Hansard No. 14 (2014), at 9678 (Andrew Damien Wilkie, independent MP); Australia, House of Representatives, 1st Sess., 7th Period, Sept. 9, 2015, Official Hansard No. 13 (2015), at 9710 (Adam Paul Bandt, Australian Greens) and 9641 (William Richard Shorten, Australian Labour Party).

61

Consider, for example, the deadline of December 31, 2016, in the approval granted by the Bundestag in December 2015.

62

Mills, supra note 26, at 1.

63

Lagassé, supra note 24, at 289.

64

Id. at 295 (citing the defense minister of the Harper government) and 296 (referring to the reassertion by PM Trudeau of “the exclusive role of the executive in military matters”).

65

Belgium, Chambre des Représentants, Commissions Réunies des Relations Extérieures et de la Défense Nationale, Compte Rendu Intégral, May 18, 2016, Parl. Doc. 54 COM 425, para. 01.04 (Karolien Grosemans): “The decision regarding deployment in Syria remains, from a strictly legal point of view, a government prerogative. This is also stated in Article 167 of the Constitution. The government has the exclusive competence to expand the mission and to deploy our F-16s in Syria.” (translation provided by the authors).

66

Id., para. 01.01 (Wouter De Vriendt) (translation provided by the authors).

67

Jeryl Bier, White House: Trump Does Not Need Congressional Approval to Strike Syria, The Weekly Standard, June 30, 2017, http://www.weeklystandard.com/white-house-trump-does-not-need-congressional-approval-to-strike-syria/article/2008682; Hubbard, Mazzetti, & Landler, supra note 37.

68

Tom Ruys, Carl Vander Maelen, & Sebastiaan Van Severen, Digest of State Practice: 1 January–30 June 2018, 5 J. Use of Force & Int’l L. 324, 352–368 (2018). See, e.g., Tanzil Chowdhury, How the Recent Strikes on Syria Undermine UK Constitutional Controls on Military Action, Law of Nations, Apr. 23, 2018, https://lawofnationsblog.com/2018/04/23/recent-strikes-syria-undermine-uk-constitutional-controls-military-action/. Note: in the immediate aftermath of the April 2018 strikes, the House of Commons library did produce a briefing paper, finding that the doctrine of humanitarian intervention—relied upon by the UK government—remains controversial and that legal opinion is divided (Richard Ware, The Legal Basis for Air Strikes against Syrian Government Targets, UK House of Commons Briefing Paper CBP-8287 (Apr. 16, 2018), http://researchbriefings.files.parliament.uk/documents/CBP-8287/CBP-8287.pdf). The research service of the German Bundestag for its part produced a report at the request of several left-wing MPs qualifying the strikes in Syria as unlawful acts of reprisal (Germany, Bundestag—Wissenschaftliche Dienste, Völkerrechtliche Implikationen des amerikanisch-britisch-franzözischen Militärschlags vom 14. April 2018 gegen Chemiewaffeneinrichtungen in Syrien, April 18, 2018, https://www.bundestag.de/blob/551344/f8055ab0bba0ced333ebcd8478e74e4e/wd-2-048-18-pdf-data.pdf/. The British House of Commons Foreign Affairs Committee, moreover, decided to conduct an inquiry into the legality of humanitarian interventions in subsequent months (ultimately siding with the British government in spite of “divisions in legal opinion,” while simultaneously calling upon the government to further clarify the general conditions for when a humanitarian intervention can take place). UK, House of Commons Foreign Affairs Committee, Global Britain: The Responsibility to Protect and Humanitarian Intervention, HC 1005, September 10, 2018, https://publications.parliament.uk/pa/cm201719/cmselect/cmfaff/1005/1005.pdf.

69

Bothe & Fischer-Lescano, supra note 14, at 198.

70

Harold Koh, Why Do Nations Obey International Law?, 106 Yale L.J. 2599, 2632 (1997); Anne-Marie Slaughter & Alec Stone, Assessing the Effectiveness of International Adjudication, 89 Proceedings of Annual Meeting ASIL 91 (1995).

71

Kurt Gaubatz, Democratic States and Commitment in International Relations, 50 Int’l Org. 109 (1996).

72

Id. at 119.

73

Sarah Kreps & Geoffrey Wallace, International Law, Military Effectiveness, and Public Support for Drone Strikes, 53 J. Peace Res. 830 (2016).

74

Jarrett Taubman, Towards a Theory of Democratic Compliance: Security Council Legitimacy and Effectiveness after Iraq, 37 N.Y.U. J. Int’l L. & Pol. 161, 181–189 (2004).

75

Zeev Maoz & Bruce Russett, Normative and Structural Causes of Democratic Peace, 1946–1986, 87 Am. Pol. Sci. Rev. 624 (1993); Håvard Hegre, Democracy and Armed Conflict, 51 J. Peace Res. 159 (2014).

76

See, e.g., Patrick Mello, Democratic Participation in Armed Conflict Military Involvement in Kosovo, Afghanistan and Iraq (2014); Sandra Dieterich, Hartwig Hummel, & Stefan Marschall, Bringing Democracy Back In: The Democratic Peace, Parliamentary War Powers and European Participation in the 2003 Iraq War, 50 Cooperation & Conflict 87 (2015); Dan Reiter & Erik Tillman, Public, Legislative, and Executive Constraints on the Democratic Initiation of Conflict, 64 J. Pol. 810 (2002).

77

Sandra Dieterich, Hartwig Hummel, & Stefan Marschall, Strengthening Parliamentary “War Powers” in Europe: Lessons from 25 National Parliaments, DFAC Policy Paper, 4 (2008a); Dieterich et al., supra note 76, at 99.

78

Jeffrey Checkel, International Norms and Domestic Politics: Bridging the Rationalist—Constructivist Divide, 3 Eur. J. Int’l Rel. 473, 480 (1997); Andrew Cortell & James Davis Jr., Understanding the Domestic Impact of International Norms: A Research Agenda, 2 Int’l Stud. Rev. 65, 66 (2000).

79

Id. at 477.

80

Andrew Cortell & James Davis Jr., How Do International Institutions Matter? The Domestic Impact of International Rules and Norms, 40 Int’l Stud. Q. 451, 456 (1996).

81

Id.

82

Consider, for instance, the absolute refusal of the Obama administration to speak of “war” during the military operations in Libya in 2011, spawning numerous online parodies including “Make love, not time-limited, scope-limited military actions!” See Ross Douthat, A War by Any Name, The New York Times, Mar. 27, 2011, http://www.nytimes.com/2011/03/28/opinion/28douthat.html.

83

Koh, supra note 70, at 2656–2657: “Political internalization occurs when political elites accept an international norm, and adopt it as a matter of government policy. Legal internalization occurs when an international norm is incorporated into the domestic legal system through executive action, judicial interpretation, legislative action, or some combination of the three.”

84

Alternatively, from a constructivist viewpoint it might be argued that it contributes to embedding these norms in the identity of the social actors involved (states).

85

This was, for example, the case in relation to the Saudi-led intervention in Yemen in 2015. See also Ruys et al., Digest of State Practice: 1 January (2015), supra note 5, at 276–277.

86

Damrosch, Democratization, supra note 12, at 287.

87

Bruno Simma, NATO, the UN and the Use of Force: Legal Aspects, 10 Eur. J. Int’l L. 1, 12–13 (1999). See Germany, Bundestag, Plenarprotokoll 13/248, Oct. 16, 1998; Germany, Bundestag, Plenarprotokoll 14/8, Nov. 19, 1998.

88

Consider, for example, the thematic debate on the legality of preventive self-defense in the Commission for External Affairs of the Belgian Senate, which took place during the drafting phase of a resolution on UN reform in February–May 2015. See Belgium, Senate, La Réforme des Nations Unies: Rapport Fait au nom de la Commission des Relations Extérieures et de la Défense par Mme. Annane et M. Galand, May 24, 2005, Doc. 3-1028/1. On the role of the international law on the use of force in the debates of the Belgian Parliament on the interventions in Afghanistan (2001) and Iraq (2003), see Eric David, La Pratique du Pouvoir Exécutive et le Contrôle des Chambers Législatives en matière de Droit International (1999–2003), 38 Revue Belge de Droit International 5, 254–268 (2005).

89

United Kingdom, House of Commons—Foreign Affairs Committee, Kosovo Crisis Inquiry: Further Memorandum on the International Law Aspects, 4th Report, June 2000, republished in (2000), 49 I.C.L.Q. 878. See also The Netherlands, Tijdelijke Commissie Besluitvorming Uitzendingen, Rapport, Sept. 4, 2000, Handelingen, TK 1999–2000, 26454, nr. 8, 287–384.

90

Canada, Senate—Standing Senate Committee on Foreign Affairs, The New NATO and the Evolution of Peacekeeping: Implications for Canada, April 2000, 7th Report, 34, http://www.parl.gc.ca/36/2/parlbus/commbus/senate/Com-e/FORE-E/REP-E/rep07apr00-e.htm.

91

The Netherlands, Commissie van Onderzoek Besluitvorming Irak, Rapport, supra note 31, at 215ff.

92

Damrosch, Democratization, supra note 12, at 288. See also supra note 31. Further, see James Green & Stephen Samuel, The Chilcott Report: Some Thoughts on International Law and Legal Advice, 22 J. Conflict & Security L. 333, 335–341 (2016) (“International law was . . . a key element to the Inquiry’s Report. The Inquiry’s commitment to international legal accuracy and clarity is evident throughout.” Id. at 339–340). Note: the Chilcott report contains a 169-page chapter on the advice on the legal basis of the Iraqi intervention. It does not, however, draw explicit conclusions on the legality of the 2003 intervention in Iraq as such.

93

Veronika Fikfak & Hayley J. Hooper, Parliament’s Secret War 18, 20, 28, 32, 48, 56 ff. (2018).

94

Id. at 18, 25–28 (pointing at a “hierarchy of fora” whereby parliamentary involvement is regarded as a tool to fill the lacuna in legitimacy that exists where no clear international mandate is present); Colin Murray & Aoife O’Donoghue, Towards Unilateralism? House of Commons Oversight of the Use of Force, 65 Int’l & Comp. L.Q. 305, 305–307, 329ff. (2016).

95

Reference can be made to the approval of the 2003 Iraq intervention by US Congress (US Senate and House of Representatives, Authorization for Use of Military Force against Iraq Resolution of 2002), H.R.J. Res. 114, Pub. L. No. 107–243, 116 Stat. 1497–1502 (Oct. 10, 2002)) or the approval by the Russian Duma of the 2014 intervention in the Crimean peninsula (Russian Parliament Approves Troop Deployment in Ukraine, BBC News, Mar. 1, 2014, http://www.bbc.com/news/world-europe-26400035). As to the former intervention, it is recalled that in the run-up to the intervention, numerous states and scholars took the view that, absent explicit Security Council authorization, it would be unlawful. In the aftermath of the intervention, general agreement seems to have emerged in legal doctrine that the 2003 Iraq war was indeed unlawful under jus ad bellum. As to the latter intervention, it is particularly telling that the UN General Assembly called upon states not to recognize any alteration to the status of Crimea. See G.A. Res 68/262, U.N. Doc. A/RES/68/262 (April 1, 2014).

96

See, e.g., Bakhtiyar Tuzmukhamedov, Russian Federation: The Pendulum of Powers and Accountability, inDemocratic Accountability and the Use of Force in International Law 278–279 (Charlotte Ku & Harold Jacobson eds., 2003). The author notes that the Russian Federation Council has never refused to give its consent to a request for authorization of foreign deployment and does not seem to be able to control the executive.

97

In greater detail, seeFikfak & Hooper, supra note 93, at 19, and chs. 4 and 6.

98

See also Murray & O’Donoghue, supra note 94, at 324, 332 (pointing to the executive’s ability to cast the issue in terms of national interest and to brand critical voices as “unpatriotic”).

99

See Inmaculada Marrero Rocha, El Discurso Jurídico en los Debates del Congreso de los Diputados: Los Casos de Kosovo y la Guerra de Irak, 57 Revista Española de Derecho Internacional 59 (2005).

100

The Netherlands, Minister van Buitenlandse Zaken, Kamerbrief inzake Advies van de Extern Volkenrechtelijk Adviseur, Prof. dr. P.A. Nollkaemper, over Luchtaanvallen op IS(IS) Doelen in Irak en Syrië, Sept. 24, 2014, Kamerstuk 27925 nr. 507 and annex; The Netherlands, Minister van Buitenlandse Zaken, Kamerbrief inzake Nader advies Extern Volkenrechtelijke Adviseur geweldgebruik tegen ISIS in Syrië, June 26, 2015, Kamerstuk 27925 nr. 543 and annex.

101

Germany, Bundestag—Wissenschaftliche Dienste, Staatliche Selbstverteidigung gegen Terroristen, Nov. 30, 2015, http://thomas-hitschler.de/wp-content/uploads/2015/11/203_15_Staatliche-Selbstverteidigung-gegen-Terroristen-aktualisierte-Version.pdf.

102

See, e.g., Arabella Lang, Legal Basis for UK Military Action in Syria, UK House of Commons Briefing Paper CBP-7404 (Dec. 1, 2015), http://researchbriefings.parliament.uk/ResearchBriefing/Summary/CBP-7404#fullreport.

103

See also United Kingdom, House of Commons, Debate, Sept. 7, 2015, Hansard Record of Commons Debate, at Column 25 (David Cameron).

104

Letter dated September 7, 2015, from the Permanent Representative of the United Kingdom of Great Britain and Northern Ireland to the United Nations addressed to the President of the Security Council, U.N. Doc. S/2015/688 (Sept. 8, 2015).

105

See United Kingdom, Parliament–Joint Committee on Human Rights, The Government’s Policy on the Use of Drones for Targeted Killing, HC 574, HL Paper 141 (May 10, 2016), http://www.publications.parliament.uk/pa/jt201516/jtselect/jtrights/574/574.pdf. See also Christine Gray et al., Op-Eds on the Joint Committee Drones Report, 3 J. Use of Force & Int’l L. 194–233 (2016). See also supra note 68, on the inquiry conducted by the House of Commons Foreign Affairs Committee after the air strikes in April 2018.

106

United Kingdom, Government Memorandum to the Joint Committee on Human Rights, http://www.parliament.uk/documents/joint-committees/human-rights/Government_Memorandum_on_Drones.pdf. However, the Committee complained about the government’s lack of cooperation, see, in particular, Government’s Policy on the Use of Drones for Targeted Killing, supra note 105, paras. 1.55, 1.56.

107

E.g., The Netherlands, Tweede Kamer der Staten-Generaal, Deelneming aan Internationale Strijd tegen ISIS, Oct. 2, 2014, Handelingen, TK 2014–2015, 9, at 9-9-3, 9-9-4, 9-9-7, 9-9-8, 9-9-9, 9-9-11, 9-9-12, 9-9-14, 9-9-15, 9-9-18. See also The Netherlands, Tweede Kamer der Staten-Generaal, Nederlandse Bijdrage Strijd tegen ISIS, July 2, 2015, Handelingen, TK 2014–2015, 104, at 104-27-1ff.

108

See, in particular, Germany, Bundestag, Plenarprotokoll 18/142, Dec. 2, 2015; Germany, Bundestag, Plenarprotokoll 18/144, Dec. 4, 2015.

109

See, e.g., Canada, House of Commons, 41st Parl., 2d Sess., Debates, Mar. 25, 2015, Hansard, vol. 147, no. 189, at 12295; Canada, House of Commons, 41st Parl., 2d Sess., Debates, Mar. 26, 2015, Hansard, vol. 147, no. 190, at 12345, 12346, 12348, 12354, 12359, 12360, 12366, 12367.

110

E.g., Belgium, Chambre des Représentants, Séance Plénière, Sept. 26, 2014, Parl Doc CRIV 54 PLEN 005, at 7, 12, 15, 21, 37, 53, 54; Belgium, Commissions Réunies des Relations Extérieures et de la Défense Nationale, Compte Rendu Intégral, May 18, 2016, Parl. Doc. CRIV 54 COM 425, paras. 01.18, 01.21, 01.27, 01.31, 01.32, 01.35, 01.36, 01.43.

111

E.g., France, Assemblée Nationale, XIVe Législature, Session Ordinaire de 2015–2016, Première Séance, Nov. 25, 2015, at 9838, 9840, 9844, 9847.

112

E.g., United Kingdom, House of Commons, Debate, Aug. 29, 2013, Hansard Record of Commons Debate, cols. 1427, 1430, 1434, 1438, 1440, 1441, 1442, 1443, 1446–1447, 1458; United Kingdom, House of Commons, Debate, Sept. 26, 2014, Hansard Record of Commons Debate, cols. 1263–1264, 1271, 1279.

113

Note: due to linguistic reasons, the authors have not been able to examine the Danish parliamentary records.

114

Canada, House of Commons, 41st Parl., 2d Sess., Vote No. 368, Mar. 30, 2015.

115

Belgium, Chambre des Représentants, Séance Plénière, June 30, 2016, Parl. Doc. 54 PLEN. 118, at 36.

116

The majority of Labour MPs voted against the government’s motion to extend military operations into Syria, although 66 of them voted in favor. See Andrew Sparrow, Cameron Wins Syria Airstrikes Vote by Majority of 174—As It Happened, The Guardian, Dec. 3, 2015, http://www.theguardian.com/politics/blog/live/2015/dec/02/syria-airstrikes-mps-debate-vote-cameron-action-against-isis-live?page=with:block-565f8399e4b05c30c3e4905f#block-565f8399e4b05c30c3e4905f.

117

United Kingdom, House of Commons, Debate, Dec. 2, 2015, Hansard Record of Commons Debate.

118

See The Netherlands, Vaste Commissies voor Buitenlandse Zaken en Defensie en de Algemene Commissie voor Buitenlandse Handel en Ontwikkelingssamenwerking, Verslag van een Algemeen Overleg, Mar. 30, 2016, Kamerstuk 27925 nr. 587, at 6 (Michiel Servaes).

119

See, e.g., Germany, Bundestag, Plenarprotokoll 18/143, Dec. 3, 2015, at 13990 (B): “Die Wahrheit ist: Der Einsatz ist weder vom Völkerrecht noch vom Grundgesetz gedeckt, was bezüglich der Bundeswehreinsätze noch engere Grenzen setzt als das Völkerrecht. Sie führen hier einen Angriffskrieg, meine Damen und Herren” (Sevim Dağdelen).

120

France, Assemblée Nationale, XIVe Législature, Deuxième Session Extraordinaire de 2014–2015, Première Séance, Sept. 15, 2015, at 7223: “une intervention hors de toute autorisation onusienne placerait la France dans l’illégalité au regard du droit international” (François Asensi).

121

William Safire, Essay: The Duty of an Opposition, The New York Times, June 8, 1981, http://www.nytimes.com/1981/06/08/opinion/essay-the-duty-of-an-opposition.html, attributing the quote to the British Lord Randolph Spencer Churchill.

122

However, whether this can be extrapolated to all states involved in the coalition against IS remains doubtful. See T. Haesebrouck, Democratic Participation in the Air Strikes against Islamic State, 14(2) Foreign Pol. Analysis 254 (2018), concluding: “The pattern of participation in the air strikes against IS does not convincingly confirm that executive or parliamentary ideology was decisive for participation in the air strikes.”

123

See also Murray & O’Donoghue, supra note 94, at 325, 332.

124

Consider, e.g., Lagassé, supra note 24, at 295 (on Canada: “Not coincidentally, the March 2008 and March 2011 votes took place during hung parliaments when the Conservatives were more politically vulnerable and acutely aware of likely elections looming on the horizon.”). Recall also the different attitude of the Belgian government with respect to the deployment of aircraft against IS in Iraq in 2014, and the subsequent expansion of the operation to Syria in 2015 (see supra note 65).

125

See, e.g., in respect of the reliance on the co-belligerency doctrine by successive US administrations and the lack of any in-depth engagement with that argument on the part of US Congress: Ingber, supra note 13, at 108, 110.

126

Reference can be made to the elaborate exposé by Craig Scott, Professor of Law at Osgoode Hall Law School (specialized in public international law and international human rights law), in the Canadian House of Commons, referring, among other things, to the position of the International Court of Justice in the Nicaragua case. See Canada, House of Commons, 41st Parl., 2d Session, Debates, Mar. 26, 2015, Hansard, vol. 147, no. 190, at 12367–12368. Similarly, the presence and interventions of Dominic Grieve, the former UK Attorney General, in the British House of Commons on legal matters seemed to carry exceptional weight. But see, for instance, Fikfak & Hooper, supra note 93, on the decrease of the number of lawyers in the UK House of Commons.

127

See, e.g., Olivier Corten, The Unable and Unwilling Test: Has It Been, and Could It Be, Accepted?, 29 Leiden J. Int’l L. 777 (2016).

128

See supra note 1. See also U.N.S.C. Res. 2169, U.N. Doc. S/RES/2169, 2 (July 30, 2014). While the authority to invite outside intervention traditionally presupposes that the territorial government exercises effective control over the state’s territory, practice suggests that the broad international recognition of the person or entity inviting outside intervention may effectively compensate to a large extent for the limited degree of effective territorial control. See Tom Ruys & Luca Ferro, Weathering the Storm: Legality and Legal Implication of the Saudi-led Military Intervention in Yemen, 65 Int’l & Comp. L.Q. 61, 85 (2016). See also generally Louise Doswald-Beck, The Legal Validity of Military Intervention by Invitation of the Government, 56 Brit. Y.B. Int’l L. 189 (1986).

129

As a matter of principle, a military intervention consented to by the de jure authorities of the territorial state does not give rise to a breach of the prohibition on the use of force under article 2(4) of the UN Charter. See Nicaragua case, I.C.J. Reports 14, para. 246. It follows that there is no need to conceptualize the territorial state’s consent as a “circumstance precluding wrongfulness” in terms of the Articles on the International Law Commission’s Responsibility of States for Internationally Wrongful Acts (ARSIWA), which raises the issue of the peremptory character of the prohibition on the use of force (which some claim to be limited to a core prohibition of “aggression” only). See Annex to G.A. Res 56/83, U.N. Doc A/56/83 (Jan. 28, 2002). See Ruys & Ferro, supra note 128. Further, Erika de Wet, The Modern Practice of Intervention by Invitation in Africa and Its Implications for the Prohibition of the Use of Force, 26 Eur. J. Int’l L. 979 (2015).

130

Further, see, e.g., Corten, supra note 127.

131

The “unable or unwilling doctrine” essentially holds that attacks by non-state armed groups can qualify as “armed attacks” triggering the right of self-defense under article 51 of the UN Charter, irrespective of self-defense. At the same time, such attacks permit the “victim State” to exercise this right by engaging in military action on the territory of another state only when the latter state is “unable or unwilling” to prevent cross-border attacks by the non-state group. Further, see Ashley Deeks, “Unwilling or Unable”: Toward a Normative Framework for Extra-territorial Self-defense, 52 Va. J. Int’l L. 483 (2012).

132

See Belgium, Chambre des Représentants, Séance Plénière, June 30, 2016, Parl. Doc. 54 PLEN. 118, paras. 06.13–06.31. Another interesting example was found in the House of Lords debates, reproduced in the Chilcott report, during which Baroness Symons laconically opined that divisions of legal opinion in international law were “nothing new.” See Chilcott Inquiry, supra note 31, at 571.

133

The second legal opinion was published in June 2015, whereas the first dates from September 2014. See supra note 100.

134

The Netherlands, Tweede Kamer der Staten-Generaal, Nederlandse Bijdrage aan de Strijd tegen ISIS, Feb. 10, 2016, Handelingen, TK 2015–2016, 53, at 53-9-10 (Michiel Servaes): “Deze missie past feitelijk een-op-een op Nollkaemper” (translation provided by the authors).

135

Germany, Federal Foreign Office, Speech by Foreign Minister Frank-Walter Steinmeier to the German Bundestag on the Debate on the Bundeswehr’s Mission against the Terrorist Organisation ISIS, Dec. 2, 2015, https://www.auswaertiges-amt.de/en/newsroom/news/-/276884.

136

United Kingdom, House of Commons, Oral Answers to Questions, Nov. 26, 2015, Hansard Record of Commons Debate, col. 1468 (Attorney General).

137

See, e.g., United Kingdom, House of Commons, Debate, Dec. 2, 2015, Hansard Record of Commons Debate, col. 465 (Stephen Doughty).

138

An interesting discussion furthermore arose in the margin between leading Belgian scholars regarding the methodological and deontological issues involved in academics participating (or steering) the public debate. See Olivier Corten, A Plea Against the Abusive Invocation of Self-Defence as a Response to Terrorism, EJIL: Talk! (July 14, 2016), http://www.ejiltalk.org/a-plea-against-the-abusive-invocation-of-self-defence-as-a-response-to-terrorism/, and comments by Pierre d’Argent (in particular).

139

See Chilcott Inquiry, supra note 31, and Green & Samuel, supra note 92, at 347–351.

140

Cortell & Davis, supra note 80, at 69.

141

See supra note 109.

142

The Netherlands, Tweede Kamer der Staten-Generaal, Deelneming aan Internationale Strijd tegen ISIS, Oct. 2, 2014, Handelingen, TK 2014–2015, 9, at 9-9-3 ff.

143

United Kingdom, House of Commons, Debate, Aug. 29, 2013, Hansard Record of Commons Debate, col. 1442.

144

Belgium, Chambre des Représentants de Belgique, Séance Plénière, June 30, 2016, Parl. Doc. 54 PLEN. 118, para. 06.13 (Dirk Van der Maelen).

145

Germany, Bundestag, Plenarprotokoll 18/143, Dec. 3, 2015, at 13897 (B) (Stefan Liebich).

146

Government’s Policy on the Use of Drones for Targeted Killing, supra note 105, at 43–48, paras. 1.31, 1.32.

147

Canada, House of Commons, 41st Parl., 2d Sess., Debates, Mar. 26, 2015, Hansard, vol. 147, no. 190, at 12367 (Craig Scott).

148

Canada, House of Commons, 41st Parl., 2d Sess., Debates, Mar. 25, 2015, Hansard, vol. 147, no. 189, at 1420 (Stephen Harper).

149

Cited (and translated) by Anne Peters, German Parliament Decides to Send Troops to Combat ISIS—Based on Collective Self-Defense “In Conjunction With” SC Res. 2249, EJIL: Talk! (Dec. 8, 2015), http://www.ejiltalk.org/german-parlament-decides-to-send-troops-to-combat-isis-%E2%88%92-based-on-collective-self-defense-in-conjunction-with-sc-res-2249/.

150

The Netherlands, Tweede Kamer der Staten-Generaal, Deelneming aan Internationale Strijd tegen ISIS, Oct. 2, 2014, Handelingen, TK 2014–2015, 9, at 9-9-4 (Geert Wilders).

151

The Netherlands, Vaste Commissies voor Buitenlandse Zaken en Defensie en de Algemene Commissie voor Buitenlandse Handel en Ontwikkelingssamenwerking, Verslag van een Algemeen Overleg, June 30, 2015, Kamerstuk 27925 nr. 560, at 45.

152

Belgium, Chambre des Représentants, Séance Plénière, June 30, 2016, Parl. Doc. 54 PLEN. 118, para. 06.02 (Karolien Grosemans) (translation provided by the authors).

153

Nicholas Watt, David Cameron Accuses Jeremy Corbyn of Being ‘Terrorist Sympathiser’, The Guardian, Dec. 2, 2015, https://www.theguardian.com/politics/2015/dec/01/cameron-accuses-corbyn-of-being-terrorist-sympathiser .

154

US Department of Defense, Speech by Stephen W. Preston: The Legal Framework for the United States’ Use of Military Force since 9/11, April 10, 2015, http://www.defense.gov/News/Speeches/Speech-View/Article/606662.

155

See Ruys et al., Digest of State Practice: 1 January (2015), supra note 5, at 294–295.

156

See, e.g., the speech by Brian Egan at the 2016 ASIL Annual Meeting, to be found at Benjamin Wittes, State Department Legal Adviser Brian Egan’s Speech at ASIL, Lawfare, April 8, 2016, https://www.lawfareblog.com/state-department-legal-adviser-brian-egans-speech-asil. Similarly, the December 2016 Report on the legal and policy frameworks guiding the United States’ use of military force and related national security operations, issued by the Obama administration, tackles both the domestic legal bases for US military force abroad as well as the international law aspects. See supra note 56.

157

E.g., see, US Senate, Committee on Foreign Relations, Hearing on United States Strategy to Defeat the Islamic State in Iraq and the Levant, 113th Cong., 2d Sess., S. HRG. 113–668 (Sept. 17, 2014), https://www.gpo.gov/fdsys/browse/committeecong.action?collection=CHRG&committee=foreignrelations&chamber=senate&congressplus=113&ycord=0 (although see a statement by (then) US Secretary of State John Kerry at 25–26: “our lawyers also are clear that Iraq has the right of self-defense, and Iraq is exercising its right of self-defense and asking the United States to help it. . . . And as a matter of right, if they are being attacked from outside their country, you have a right of hot pursuit. You have a right to be able to attack those people who are attacking you as a matter of self-defense.”); US Senate, Committee on Armed Services, Hearing on U.S. Policy towards Iraq and Syria and the Threat Posed by the Islamic State of Iraq and the Levant (ISIL), 113th Cong., 2d Sess., S. HRG. 113–589 (Sept. 16, 2014), https://www.gpo.gov/fdsys/browse/committeecong.action?collection=CHRG&committee=armedservices&chamber=senate&congressplus=113&ycord=0; US House of Representatives, Committee on Foreign Affairs, Hearing on the ISIS Threat: Weighing the Obama Administration’s Response, 113th Cong., 2d Sess., Serial No. 113–219 (Sept. 18, 2014), https://www.gpo.gov/fdsys/browse/committeecong.action?collection=CHRG&committee=intrelations&chamber=house&congressplus=113&ycord=0; US House of Representatives, Committee on Armed Services, Hearing on the Administration’s Strategy for the Islamic State in Iraq and the Levant, 113th Cong., 2d Sess., HASC No. 113–126 (Sept. 18, 2014), https://www.gpo.gov/fdsys/browse/committeecong.action?collection=CHRG&committee=armedservices&chamber=house&congressplus=113&ycord=0.

158

See supra note 55.

159

What is particularly remarkable in this context is that the US executive branch has based its expansive interpretation of the congressional authorization to use military force (the AUMF 2001) on a doctrine that is borrowed from international law. Specifically, the executive branch has argued that the AUMF 2001 authorizes the use of force against al-Qaeda, the Taliban and “associated forces,” and that the latter notion must be understood in accordance with the doctrine of co-belligerency under neutrality law. The executive branch has thus—controversially—sought to rely on permissive rules of international law in order to claim an expansive interpretation of its powers under domestic law. Paraphrasing the famous US Supreme Court judgment, Ingber labels this “power-enhancing interpretive mechanism as a Reverse Betsy.” Ingber, supra note 13, at 79. Ingber, moreover, expresses regret regarding how members of Congress made little effort to critically examine the executive’s (artificial) co-belligerency argument. She concludes that “the Executive’s invocation of a little known concept from international law to interpret its domestic statutory authority enabled it to promote a flexible and ultimately expansive understanding of that authority with very little pushback from the courts or Congress.” Id. at 115–116.

160

For an in-depth analysis of the crime of aggression under the Rome Statute, seeThe Crime of Aggression: A Commentary 2 vols. (Claus Kreβ & Stefan Barriga eds., 2017).

161

Yoram Dinstein, War, Aggression and Self-defence 139 (5th ed. 2011).