Transnational Activism and Domestic Politics: Arms Exports and the Anti-Apartheid Struggle in the UK–South Africa Relations (1959–1994)

In 1964, the UK government imposed an arms embargo on South Africa, which it maintained until the end of the white minority rule. What explains this embargo? Using mainly archival evidence, this paper demonstrates that domestic political dynamics in the United Kingdom mediated the inﬂuence of the transnational anti-apartheid and anti-colonial struggles on the British government. The United Kingdom imposed and maintained this embargo due in part to a domestic advocacy network, whose hub was the Anti-Apartheid Movement. The paper provides a comprehensive explanation of an important issue in British foreign policy, the anti-colonial struggle, and Southern Africa’s history. There are theoretical implications for foreign policy analysis concerning the role of advocacy networks, in- teractions between local and global activism, the role of political parties’ ideology and contestation, the effects on foreign policy of changes in a normative environment, the effects of norm contestation, and normative determinants of sanctions. du Mouvement anti-apartheid. Cet article offre une explication complète d’une question importante de la politique étrangère britannique : la lutte anti-coloniale et l’histoire d’Afrique du Sud. Cet article a des implications théoriques pour l’analyse des politiques étrangères s’intéressant au rôle des réseaux de plaidoyer, aux interactions entre activisme mondial et lo- cal, au rôle des partis politiques, à l’idéologie et à la contestation, aux effets des changements de l’environnement normatif sur la politique étrangère, aux effets de la contestation des normes, et aux déterminants normatifs des sanctions. This explores potential determinants of this behavior through a case study of the arms embargo imposed by Kingdom on Africa 1964 and maintained until the white minority rule. This case is important for the validity of explanations about decisions regarding arms exports for a few reasons. First, it provides an opportunity to examine


Introduction
Why do governments promote arms exports in certain situations but restrict them in others? Scholarly work from the realist tradition emphasizes the strategic logic of these decisions, arguing that governments use arms sales instrumentally to strengthen their security or the security of allies, increase interoperability with other militaries, form or maintain alliances, or gain access to political and military elites (Brzoska and Ohlson 1987;Catrina 1988;Laurance 1992;Stohl and Grillot 2009;Yarhi-Milo, Lanoszka, and Cooper 2016;Raska and Bitzinger 2020). From this standpoint, governments restrict arms exports only if sales of weapons are expected to strengthen adversaries, diffuse certain sensitive technologies, escalate conflicts that may damage their short-or long-term interests, or cause an economic loss.
However, governments often justify restrictions on arms exports based on concerns about human suffering caused by conflicts, oppressive regimes, or violent governments. These restrictions are frequently in the form of partial or full arms embargoes, often imposed in response to acts of violence, coups d'état, or wars. For example, in 1989, the European Economic Community (EEC) imposed an arms embargo on China a few days after the violent suppression of protests in Beijing. In 1995-1996, the European Union and the Commonwealth imposed an embargo on Nigeria after the execution of Ken Saro-Wiwa and the other Ogoni nine. In 1996, the European Union imposed an embargo on Afghanistan, two months after the start of the Taliban's rule. What explains this behavior? Is it due to concerns about human suffering or a cover for underlying interests?
This paper explores potential determinants of this behavior through a case study of the arms embargo imposed by the United Kingdom on South Africa in 1964 and maintained until the end of the white minority rule. This case is important for the validity of explanations about government decisions regarding arms exports for a few reasons. First, it provides an opportunity to examine the potential influence of decolonization and the anti-colonial struggle on arms export behavior, as well as their interactions with Cold War dynamics. If a Cold War mindset shaped decisions concerning arms exports, the UK government should have supported South Africa: arms sales could be used to expand or create spheres of influence, and Africa was an important battleground between the Western and Eastern blocs. However, decolonization made the international system-and foreign policy decision-making-more complex: African, Asian and, to some extent, Latin American governments opposed the apartheid regime and considered it a colonial legacy. They pressured other governments, international organizations, and corporations Rodrigo Fracalossi de Moraes is a Researcher at the Institute for Applied Economic Research (Ipea), a think tank with offices in Brasília and Rio de Janeiro. He received the DPhil in International Relations from the University of Oxford in 2018 and previously taught at the University of Oxford's Diplomatic Studies Programme. His research interests focus on the regulation of dangerous products (weapons and pesticides, for example) and the role of social norms and networks in global governance. Before joining academia, he was an officer in the Brazilian Army.
to impose sanctions against South Africa or supported those that fought against the apartheid. Opposition to the apartheid was amplified by an international norm environment in which the existence of colonies and white minority governments had become illegitimate. This produced a tension between a Cold War mindset and postcolonial normative pressures. Second, in a context of imperial decline, arms sales played an important role for Britain: they were a power resource that the United Kingdom could instrumentally use to minimize its loss of influence on other countries' policies. And there were specific geostrategic incentives to provide weapons to South Africa: there was a bilateral agreement regarding the use of the Simonstown Naval Base; South Africa was adjacent to or surrounded British protectorates; and South Africa played a central role in countering Soviet influence in Southern Africa. Third, the United Kingdom imposed this embargo, but other major arms exporting countries in the West (France, for example) did not-or did it later. This opened part of the South African arms market for other countries, thus reducing incentives for the United Kingdom to maintain the embargo.
The proximate cause of the embargo was Labour Party's victory in the 1964 general election, which imposed the embargo (against the wishes of the Conservatives). Yet, this raises at least two questions: why did the Labour government support and impose this embargo? Why did Conservatives maintain it when in power? This paper argues that the embargo was imposed and maintained due in part to norm-driven pressures from a domestic advocacy network, whose hub was the Anti-Apartheid Movement (AAM)-a group founded by South African exiles. Members of this network navigated the political system in Britain, increasing the political salience of the anti-apartheid struggle in the United Kingdom and the tension between the instrumental use of arms sales and norm-driven pressures. The AAM and other groups internalized the global anti-apartheid struggle into British domestic politics, stressing the anachronism of white minority rule, the need for promoting African people's liberation, and the contradictory behavior of the UK government, which sold weapons to the National Party-led government while granting independence to colonies in Africa. They framed the fight against apartheid as an anti-colonial and anti-racist struggle, which made it more likely to resonate with government officials, political parties, and the public.

Theoretical Framework and Research Design
If exporting weapons often brings economic and political benefits for exporting countries, why do governments impose restrictions on their own arms exports? There are at least three possible explanations. First, decisions concerning arms transfers may be based on states' material interests. Governments would impose restrictions on arms sales to weaken perceived adversaries, prevent diffusion of sensitive technologies, or prevent certain conflicts from escalating. Concerns about human suffering might be used to justify these decisions, but they would be a disguise for ulterior motives, "tools of manipulation, used to dress up self-interest in more acceptable garb" (Elster 1989, 125). This perspective is reinforced by scholarly work arguing that the existence of democratic institutions does not influence arms export behavior (Perkins and Neumayer 2010;De Soysa and Midford 2012;Hansen and Marsh 2015;Johnson and Willardson 2018). These findings suggest that underlying material interests are likely to explain arms export policies and practice, with a few of these authors arguing that arms sales are an expression of "organized hypocrisy." Second, from a normative perspective, concerns about negative impacts of arms sales derive from norms, which are real and autonomous (Elster 1989, 125;Parekh 1997, 54;Wheeler 2000, 39). Arms export restrictions would be imposed because providing weapons to certain customers (oppressive governments, for example) or selling certain types of weapons violate shared norms. Previous research examined the determinants of arms control policies from this standpoint, looking at the potential influence of norm-driven campaigns by transnational or domestic advocacy networks. This literature demonstrates how transnational activism contributed, for example, to the landmine ban (Price 1998;Cameron, Lawson, and Tomlin 1998;Rutherford 2000Rutherford , 2011, the cluster munition ban (Bolton and Nash 2010), and stricter rules related to small arms and light weapons (SALW) (Krause 2002(Krause , 2004(Krause , 2014Garcia 2006Garcia , 2009Garcia , 2011. Third, states may impose restrictions on arms exports due to concerns about their reputation among either domestic or international audiences (Erickson 2015). In a norm environment where being responsible requires not selling weapons to oppressive governments, for example, governments may prohibit an arms deal if this is expected to give them a reputational benefit (or prevent a reputational cost) among domestic audiences or in the international society, the latter equivalent to what Finnemore and Sikkink (1998) call the "desire to enhance international legitimation." In the case analyzed in this paper, the main question is: why did the United Kingdom impose an arms embargo on South Africa in 1964 and maintain it until the end of the white minority rule? I initially tested the hypothesis that this was due in part to normative pressures from a domestic advocacy network, whose hub was the AAM. This hypothesis draws from literature looking at how domestic networks translate transnational campaigns into political action, in this way mediating the influence of transnational activism on governments' behavior. Brysk (1993) demonstrated that civil society groups in the United States managed to influence Carter's government concerning bilateral aid to Argentina's military regime. Klotz (1995Klotz ( , 1999 demonstrated how domestic groups in the United States influenced the government's position toward South Africa during the apartheid. Dubow (2017) stressed that the transnational anti-apartheid struggle was constituted by a set of distinctive national movements, demonstrating how domestic politics mediated the influence of a transnational struggle.

H1: A domestic advocacy campaign made the imposition and maintenance of an arms embargo against South Africa more likely.
This hypothesis draws also on Krause (2014), who argued that civil society campaigns are more likely to succeed when groups focus on a single and easy to communicate goal (banning arms sales to South Africa, for example), and Keck andSikkink (1998, 1999), who argued that campaigns on issues related to bodily harm-and with a clear causal chain between a targeted actor and victims-are more likely to succeed. The fact that arms cause bodily harm and British-manufactured armored cars were used during the Sharpeville Massacre explains in part why the UK government imposed an arms embargo, but not other types of sanctions (trade sanctions, for example).
The UK arms embargo was not a simple by-product of a global movement against the apartheid, but neither it was a mere reflection of Labour's victories in general elections: the appropriateness of selling weapons to South Africa-and of the types of weapons that might be sold-was strongly contested. After 1964, the embargo itself was not heavily contested, but its application was. Within both Labour and Conservative Parties, a central point of contestation was on whether sales of weapons for "external defense" should be authorized. Drawing on theoretical and empirical work about the effects of norm contestation (Wiener 2008(Wiener , 2014McKeown 2009;Panke andPetersohn 2012, 2016;Kutz 2014;Bellamy 2015;Deitelhoff andZimmermann 2019, 2020;Stimmer 2019), I tested whether contestation over the application of the arms embargo clarified the scope of the norm and made the inappropriateness of selling arms to South Africa more robust. I consider that norm robustness is high when "its claims are widely accepted by norm addressees (validity) and generally guide the actions of these addressees (facticity)" (Deitelhoff and Zimmermann 2019).

H2: Contestation over the arms embargo application clarified the scope of the norm (weapons should not be sold to South Africa) and reinforced its robustness.
This article is situated within literature that reconciles the global and local dimensions of transnational activism, especially of the anti-apartheid struggle. Although the anti-apartheid struggle was global, it should be seen "not only as a transnational movement but also as a series of discrete local struggles with distinctly national features" (Dubow 2017). Previous research examined civil society or government opposition to South Africa's apartheid in the United States (Klotz 1995(Klotz , 1999Culverson 1996;Minter and Hill 2008), the United Kingdom (Gurney 2000(Gurney , 2009Fieldhouse 2005;Thörn 2006;Skinner 2009), Sweden (Thörn 2006), India (Lissoni 2019), China (Taylor 2000, and the Soviet Union (Shubin 2008), as well as the main global features of the struggle (Thörn 2006;Sapire and Saunders 2012;Konieczna 2019). The literature also examined specific dimensions of the transnational anti-apartheid struggle, as those related to black solidarity (Klotz 1995;Klotz 2002;Nesbitt 2004;Williams 2015), liberal humanitarianism (Skinner 2010), sporting boycott (Morgan 2017), political prisoners (Klein 2009), and investment (Kaempfer, Lehman, and Lowenberg 1987). However, the literature has not explored in-depth campaigns against arms sales, which were a central-and successful-issue in the anti-apartheid struggle. Important exceptions are Young (1998) and Bale (1997), who specifically examined discussions around the imposition of the 1964 UK arms embargo and those within the UK Labour Party in 1967 over a possible resumption of arms sales.
A seminal work in the literature about the transnational dimension of the antiapartheid struggle is Klotz (1995Klotz ( , 1999Klotz ( , 2002, who looked at the influence of the anti-apartheid struggle on government policies toward South Africa, with a focus on US policies. Among other points, she argued that the AAM did not succeed in influencing the British government-different from what happened in the United States. In contrast, I present evidence of a broad anti-apartheid network in the United Kingdom in the early 1960s, which led the UK government to impose an arms embargo before other governments and around twenty years before the economic sanctions imposed on South Africa in the mid-1980s. These findings are similar to those of previous research (Gurney 2000(Gurney , 2009Fieldhouse 2005;Thörn 2006;Skinner 2009;Sapire and Saunders 2012). Moreover, this paper problematizes the role of political parties, how their positions are formed, and the impacts of party contestation, which is a topic largely unexplored in the foreign policy literature beyond the cases of the United States and of party positions concerning the European Union (Raunio and Wagner 2020).
This paper looks at the period from 1959 to 1994, between the foundation of the Boycott Movement in the United Kingdom and the end of the white minority rule in South Africa. Focus is greater on the period until 1977. This is due to the 1977 United Nations Security Council (UNSC) mandatory arms embargo, which further decreased the legitimacy of arms sales to South Africa and made it a violation of international law. By focusing on this period, it is possible to remove the effect of the 1977 mandatory multilateral embargo on the UK government behavior. Moreover, the period until 1977 mostly coincides with what Dubow (2015) calls "high apartheid," a period dominated by an "explicit hyper-racism." The paper uses archival evidence from the UK government at The National Archives and from the AAM at the Bodleian Libraries, besides semi-structured interviews with Robert Hughes (former AAM's chair and MP), Michael Heseltine (former defense secretary), and Christabel Gurney (former activist at the AAM and editor of the Anti-apartheid News). Information from these sources was triangulated with secondary sources, especially those examining the history of the AAM (Gurney 2000(Gurney , 2009Konieczna and Skinner 2019) and of British arms sales (Phythian 2000).

Anti-Colonialism and the Anti-Apartheid Struggle in the United Kingdom: At the Intersection of Domestic, Transnational, and Interstate Politics
In the early 1960s, the South African government was becoming increasingly isolated. In 1960 (the "year of Africa"), seventeen African countries became independent, increasing pressures against the apartheid system at the United Nations and elsewhere. Harold Macmillan's "wind of change" speech in South Africa in February 1960 contributed to reinforce perceptions of isolation among South African authorities (Irwin 2012). These perceptions were further strengthened by the international commotion caused by the Sharpeville Massacre in March 1960. This context added to Verwoerd government's already favorable stance toward turning South Africa into a republic, contributing to the October 1960 referendum and its result. In March 1961, South Africa withdrew its application to rejoin the Commonwealth (anticipating a rejection), which had become an important stage for African and Asian countries to criticize the apartheid and demand sanctions (Thörn 2006, 71;Irwin 2012). As additional evidence of its increasing isolation, the United Nations General Assembly resolution 1761 created the United Nations Special Committee against Apartheid and called for various sanctions. In 1963 and 1964, the UNSC resolutions 181, 182, and 191 called for an arms embargo against South Africa-though in part attenuated by the British and French abstentions in the UNSC 181 resolution. Although this period marked the end of "special postcolonial affinities" between the United Kingdom and South Africa-which had characterized bilateral relations for fifty years (Dubow 2013, 41)-the UK Conservative government did not stop arms sales to South Africa and did not interrupt negotiations of new arms deals. However, a Labour government imposed an arms embargo when it took office in 1964. What explains this policy change?

Campaigning for an Arms Embargo: How the Inappropriateness of Arming South Africa
Emerged in UK Domestic Politics (1959-1964 I argue that the decision to impose this embargo was due in part to activities of a domestic anti-apartheid network-whose hub was the AAM. The AAM was founded as the Boycott Movement in 1959, after Hendrik Verwoerd took office in South Africa, whose government combined a strengthened version of apartheid with larger military and police apparatuses. The Boycott Movement was founded by exiled South Africans and aimed at internationalizing a boycott campaign against firms supporting the National Party. This campaign had been launched earlier that year by the South African Congress movement as part of a broader campaign against pass laws (Gurney 2000;Thörn 2006, 128). Over thirty-five years, the AAM constructed a network of academics, churches, other civil society groups, MPs, political parties, journalists, students, and trade unions, contributing to increase the political salience of the anti-apartheid struggle in UK politics. The movement found a fertile ground for politicization in Britain, opposing Conservatives and the business community on one side (who were initially against any sanction), and students, Christian groups, the black community, and many on the left on the other side, for whom the apartheid represented racism and colonial oppression (Gurney 2000). The expansion from a boycott movement to a broader campaign occurred after the Sharpeville Massacre, when sixty-nine people were killed in a protest against the pass laws (Young 1998, 63;Gurney 2000;Thörn 2006, 127). British-made armored cars were used during the massacre, exposing a clear link between Britain and oppression in South Africa. 1 The Boycott Movement changed its name to AAM and started pressuring the British government to stop arms sales. According to Christabel Gurney, a former activist at the AAM, the issue of arms sales was picked by the AAM because it was a "very obvious thing to campaign on since the South African regime was aggressively internally, keeping down opposition," which had become especially clear with the use of British weapons in Sharpeville. 2 As an example of how issues involving bodily harm and with a short causal chain are more likely to resonate (Keck and Sikkink 1998), Christabel Gurney emphasized that the AAM's main goal was to isolate South Africa in every sphere, but they "quickly discovered that there was a much wider breadth of support for campaigning against arms supplies than for most other issues. For example, the churches were opposed to the arms sales but for a very long time did not want to campaign against investment and trade." 3 The significance of this should not be underestimated: the campaign against arms exports was the most important for the AAM in the early 1960s. 4 An advocacy network already existed around the Boycott Movement/AAM in the late 1950s and early 1960s, including the Movement for Colonial Freedom, Christian Action, the African Bureau, Committee of African Organizations, some trade unions, the churches, student bodies, the National Council for Civil Liberties, and segments of the Labour Party (Gurney 2000;Thörn 2006, 130). The British Council of Churches, for example, stressed in December 1963 the importance of the 1963 UNSC resolutions and emphasized that many governments had prohibited arms sales to South Africa. This document was forwarded to Harold Wilson by David Ennals, who was both secretary of the Labour Party's international department and AAM's chair. 5 Support from trade unions contributed to influence the Labour Party's position and to the development of an organic relationship between Labour and the AAM-a point stressed by Robert Hughes, MP (1970MP ( -1997 and AAM's chair (1976)(1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995). 6 This broad support indicates that the AAM was not a "branch" of the African National Congress (ANC) or the Pan Africanist Congress of Azania in Britain, although it depended on them for legitimacy and provided a platform for them in the United Kingdom. The importance of a movement adapted to the characteristics of UK politics was emphasized by Abdul Minty (honorary secretary of the AAM) and-according to him-by Oliver Tambo, for whom the AAM should be a distinctive British movement (Onslow and Minty 2013).
The Boycott Movement/AAM did more than pressuring the UK government from outside the state. In the late 1950s and early 1960s, the Boycott Movement/AAM and Labour Party members engaged with each other, which led segments of the Labour Party (the Labour Party Young Socialists (LPYS) and various Constituency Labour Parties [CLPs], for example) and some of its leaders (Barbara Castle, for example) to become part of the British movement against apartheid. Labour had a crucial role in turning the anti-apartheid struggle into a politically salient issue in the United Kingdom. Although the anti-apartheid struggle was not a central topic for the party in the late 1950s, its unexpected defeat in the 1959 election led Labour leaders to look for an issue that could unite the party, concluding that the campaign to boycott South African goods was a good fit (Gurney 2000). 7 Moreover, although the Labour Party was not-at that time-officially committed to supporting the anti-colonial struggle, members of the Labour movement and a few major Labour leaders-Barbara Castle, for example-supported it (Gurney 2000;Owen 2013). Labour's support gave a greater scale to the AAM's activities: it increased the number of anti-apartheid conferences, the number of local committees, the distribution of publicity material, and support from trade unions (Gurney 2000). Harold Wilson (then an MP and later leader of the Labour Party) became personally involved in the anti-apartheid struggle. In 1962, he and Barbara Castle (then-AAM's president) questioned then-Lord Privy Seal Edward Heath on sales of tear gas to South Africa. 8 In 1963, Harold Wilson-recently elected leader of the Labour Party-was persuaded by Abdul Minty and Barbara Castle to participate in a rally organized by the AAM in London: the No British Arms for Apartheid, when he gave a speech criticizing arms exports to South Africa and pledging an embargo if elected (Phythian 2000, 5;Onslow and Minty 2013). 9 Although the Labour Party used the 1963 and 1964 UNSC resolutions against South Africa to reinforce its stance concerning the need for an embargo, Labour's position predated the UNSC resolutions, suggesting that an embargo would have been imposed even in their absence. 10 Imposing, Keeping, and Reinforcing the UK Embargo (1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976)(1977) When Labour took office in 1964, it imposed an arms embargo. In this way, it fulfilled a campaign pledge and turned an emerging norm (the inappropriateness of arming South Africa) into government policy. This decision was motivated by factors other than economic and geostrategic incentives as these had not changed since the previous Conservative government. South Africa was buying increasing amounts of British weapons-around 10 percent of them just before the embargo-as seen in figure 1. 11 Moreover, South Africa's reaction to an arms embargo could not be ignored due to three factors of geostrategic importance: (1) a bilateral agreement for using the Simonstown Naval Base; 12 (2) the fact that Basutoland, Bechuanaland, and Swaziland were surrounded by or adjacent to the South African territory; and (3) the role of South Africa in the struggle against communism-a "card that the South African government played very hard." 13 South African reaction could be especially negative because the United Kingdom was its main provider of weapons from 1950 to 1964. Arms were essential to keep the white minority rule, control South West Africa, deter neighboring countries from supporting liberation movements in South Africa and, later, to support Smith's regime in Rhodesia and intervene in Angola and Mozambique.
Had the Conservative Party won the 1964 general election, an embargo would probably have not been imposed. However, it is insufficient to conclude that the embargo depended only on the political party in power because Labour's position resulted from an organic relationship that it developed with the AAM. This puts into perspective the notion of opposing preferences and separateness between  1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969  civil society groups and governments. Boundaries between state and civil society are not static and are often blurred. Issues that emerge in civil society-and can be politically peripheral-may later be incorporated into state policies. There is also a grey zone between civil society and the state: "some institutions, like parties, straddle the border by definition" (Shaw 1994, 659). The relationship between the AAM and the Labour Party developed through at least two channels. First, through local constituencies and groups within the party sympathetic to the anti-apartheid struggle. Members of the AAM were often also members of the Labour Party, and various CLPs had local anti-apartheid groups-forty-five of which were members of the AAM in 1968. 14 Some CLPs elected representatives that defended the anti-apartheid cause, in this way taking this agenda to the National Executive Committee, the House of Commons, and eventually the British government. 15 There is extensive correspondence showing interactions between the AAM and CLPs: the AAM asked for support from CLPs, CLPs asked for support from the AAM, 16 and CLPs donated money to the AAM. 17 Another link was through the LPYS, which offered political support to the AAM and distributed material for campaigns. 18 In exchange, the AAM asked the LPYS to lobby the government against military collaboration with South Africa, 19 and for the presence of LPYS members in anti-apartheid demonstrations. 20 Second, through contacts between AAM leaders and Labour leaders or MPsor even direct participation of Labour politicians in the AAM-as in the cases of Barbara Castle, David Ennals, Eric Moonman, Frank Judd, Gerald Kaufman, Harold Wilson, Ian Mikardo, Joan Lestor, Judith Hart, Reg Prentice, Richard Wainwright, and Robert Hughes. When Labour was in power, the AAM had easier access to "gatekeepers" in government due to these connections. This was important because Labour governments did not meet all AAM's demands, so it remained under pressure from the AAM and within the party. Although an arms embargo was imposed in 1964, there were discussions within government in 1967 about possibly relaxing it for sales of naval equipment. This caused a division in Cabinet: the foreign secretary George Brown and the Minister of Defence for Equipment Roy Mason were in favor of relaxing the embargo while Harold Wilson and Barbara Castle were against. Proposals for relaxing the embargo were criticized within the Labour Party and outside it, leading the government to maintain it as it was (Phythian 2000, 10-14). Contestation, however, made the embargo-and the norm on which it was based-more robust and clarified the scope of the norm and Labour's position: there is no evidence that any major Labour politician proposed relaxing the embargo after 1967.
Contestation over Rhodesia's independence also indicate the political salience of the anti-apartheid struggle in UK domestic politics, as well as the influence of a postcolonial normative environment on Britain's stance toward Rhodesia and South Africa. Before the Unilateral Declaration of Independence (UDI) in November 1965, Britain made clear that independence would be granted only if the Rhodesian Front accepted a set of five (later six) principles, whose ultimate goal was the implementation of majority rule. Yet, Ian Smith rejected these principles, a decision that was soon followed by the UDI. Had a Cold War mindset prevailed, the UK government would probably have articulated a potential bloc with South Africa, Portugal, and white nationalists in Rhodesia to counter Soviet influence. Instead, the UK government adopted broad sanctions against Rhodesia and maintained the arms embargo on South Africa, whose justification was based in part on South Africa's support to white nationalists in Rhodesia, its support to the Portuguese Colonial War, and the occupation of Namibia. 21 The anti-apartheid struggle was considered-and framed-by the AAM-led network as part of a single anti-colonial struggle in Southern Africa. For the AAM, there was "an indivisible complex" in Southern Africa that included South Africa's apartheid, the white minority government in Rhodesia, and the colonial wars in Angola and Mozambique, a position that influenced UK policy toward Southern Africa. 22 In 1970, when Edward Heath took office, his government planned to relax the embargo so that a few types of weapons-especially naval equipment-could be exported. 23 Conservatives argued that this was necessary due to legal obligations, commercial interests, and to counter Soviet expansion in the Indian Ocean. 24 In reaction, the AAM created the campaign Stop Arms for Apartheid South Africa, Although Heath was in favor of resuming arms sales, he made clear that sales of weapons used for internal repression would not be authorized. Moreover, Foreign Secretary Alec Douglas-Home argued that the United Kingdom should export only "equipment for maritime defence directly related to the security of the sea routes as provided for in the Simonstown agreements." 29 This implied that weapons used to support Smith's regime in Rhodesia, for example, would not be exported, which was a central issue in the AAM's campaigns (Minty 1977). A Conservative government therefore complied with a norm and maintained a policy introduced by a Labour government, even in the absence of a mandatory international embargo and regardless of whether other countries exported weapons to South Africa. This stance indicates that the norm was respected in their practical (compliance) and discursive (legitimacy) dimensions: the UK government's behavior and discourse were consistent with the norm.
Arms exports to South Africa were limited during Heath's government. Except for sales of Wasp helicopters-which faced a large opposition campaignno substantial agreements were signed, indicating that the inappropriateness of arming South Africa was embedded in government policies. While in the early 1960s there was contestation on whether an embargo should be imposed, in the early 1970s the scope of contestation was narrower: Conservatives agreed with keeping the embargo, contesting only whether specific types of weapons-naval equipment, mainly-could be exported. Despite Conservatives' emphasis on the need to contain communism in Southern Africa and broader foreign policy ambitions, they were constrained by the international and domestic scrutiny of policies toward South Africa. This was due to a transnational and domestic norm environment in which supporting South Africa was largely considered inappropriate. Moreover, contestation over the application of the norm during Heath's government reinforced the norm's robustness as it clarified and consolidated the range of cases on which the embargo should be applied, indicating once more-as it had during the 25 Bodleian: MSS/AAM-1494. No arms to South Africa (ad hoc planning group), letter to various groups aimed at organizing a campaign, September 16, 1970; MSS/AAM-779. AAM, letter from S. Abdul to Harold Wilson, November 11, 1967. 26 Bodleian: MSS/AAM-13. AAM, annual report 1970AAM, annual report -1971 previous Labour government-that selling weapons to South Africa was inappropriate even in the case of arms for external defense. The AAM welcomed the return of Labour to power in 1974, in a context in which the Labour Party had officially committed to supporting liberation movements in Southern Africa. 30 The Labour government cancelled the contract to supply Wasp helicopters signed by the previous government (of which there was one unit yet to be delivered) and decided that it would not authorize any arms deal with South Africa. 31 In 1976, however, the AAM sent a memorandum to prime minister James Callaghan with a list of cases in which the embargo was-according to the AAMbeing breached, highlighting the supply of tropospheric scatter systems by Marconi, used to maintain the occupation of Namibia. 32 Despite these cases, the embargo remained and was enforced by Harold Wilson's and James Callaghan's governments. Moreover, the Labour conference of 1977 stated that a Labour government should "support a UN mandatory arms embargo, seek to end any collaboration by NATO or NATO powers, and tighten up the existing embargo." 33 The norm remained robust even in a context in which Southern Africa had gained weight in the anti-communist struggle due to the independence of Mozambique and Angola, coming to power of the Liberation Front of Mozambique and People's Movement for the Liberation of Angola (MPLA), and Cuba's military support to the MPLA. Also, Labour's support remained even though the AAM was often perceived as being too far to the left due to its connections with the ANC (Gurney 2009).
Negotiations concerning Rhodesia also provide evidence that the inappropriateness of arming South Africa was embedded in UK policies. Over 1974-1979 Africa, the United States, and the United Kingdom pressured Smith's regime, pushing it to negotiate with African nationalist leaders. Though there were failed talks (including the ones at the Geneva Conference and on HMS Tiger in 1976), these pressures contributed to steer the "Rhodesia issue" toward a settlement, which eventually became the Internal Settlement of March 1978 and, later, the Lancaster House Agreement of December 1979 (Kandiah and Onslow 2008). Participating in negotiations regarding Rhodesia aimed at improving South Africa's reputation, in a context of international outcry following the Soweto uprising and international pressures regarding Namibia (Day 1978;Kandiah and Onslow 2008;Onslow 2009bOnslow , 2009a. However, neither the combined pressures of the United Kingdom, the United States, and South Africa nor the negotiations that eventually led to the end of Smith's regime changed the UK policy toward South Africa, which remained under an arms embargo until 1994.
Although Labour imposed an embargo and Conservatives maintained it, the UK government was never willing to impose trade or investment sanctions. When discussions on terminating the Simonstown Agreement were conducted, for example, there were serious concerns about potential impacts on the overall trade with South Africa. 34 Also, in 1976Also, in -1977 and France a potential veto on a UNSC mandatory arms embargo. 35 Yet, opposition to economic sanctions was driven by perceived high economic costs rather than a Cold War mindset.
Monitoring Compliance with the 1977UNSC Embargo (1977-1994 There was no serious violation of the embargo by Britain from the late 1970s until the end of the white minority rule in South Africa. This was in great part due to the UNSC 1977 mandatory embargo, which covered both new equipment and spare parts. However, Thatcher initially pursued a less strict interpretation of the embargo. In 1980, Foreign Secretary Peter Carrington-one of the "wets"-proposed that arms exports to South Africa should be stricter, covering not only military equipment, but also dual-use products. Thatcher disagreed, expressing concerns about losing potential deals, which was backed by the secretaries for trade, John Nott, and defense, Francis Pym. 36 Moreover, Thatcher's attitude toward civil society groups defending arms control and disarmament was negative, which is indicated by her stance on the Campaign for Nuclear Disarmament (CND). When Michael Heseltine was appointed defense secretary, one of his main tasks was to build a counter-narrative against the CND: The CND was essentially directed at the Ministry of Defence when I was secretary of state. It was the subject of bitter controversy leading up to the 1983 general election. And one of the reasons why Mrs Thatcher put me in that position was to put me into the frontline in defence of government policy on that issue. 37 Heseltine affirmed that the CND's purpose was to "argue the cause of the Soviet Union at the expense of the free societies of the West." He sent a letter to Conservative MPs and candidates with "biographical details of the communists, Marxists and socialists in the CND movement" (Heseltine 2000, 244-47). Thatcher's negative attitude is indicated also by her comments about the AAM: in a government dossier, she stressed that the AAM was "heavily influenced by Communists or Communist sympathizers" and that most South African exiles at the AAM were "current or former members of the South African Communist Party." 38 Heseltine also emphasized that unilateral restrictions on arms sales have no impact on the military capabilities of an arms importer, as other arms exporting countries will supply the demanded weapons. 39 However, no significant arms deal was signed with South Africa during either Thatcher's or John Major's premierships. Archival evidence suggests that activities of the AAM and Labour made the UK government less likely to breach the 1977 UNSC arms embargo. AAM's focus was then on monitoring the UK government behavior to make sure it complied with the 1977 embargo. 40 In 1982, the Foreign and Commonwealth Office (FCO) stressed in a report sent to Thatcher that "we remain under considerable pressure from the AAM's activities in the UK." The fact that Thatcher added comments to the document-expressing concerns about Labour and Liberal support to the AAM-indicates how this issue was a matter of concern 35 TNA: PREM 16/1462. for her. 41 Moreover, the AAM had consolidated over the 1970s a large supporting base, including trade unions, the churches, and local groups, which expanded its ability to pressure the Conservative government (Gurney 2009

Alternative (or Complementary) Explanations for the UK Arms Embargo
There are at least four alternative-or complementary-explanations for why the United Kingdom imposed and maintained this arms embargo. First, African and Commonwealth countries vehemently criticized Britain for selling arms to South Africa-or considering to do so-and threatened to retaliate the United Kingdom. This was a point of concern for the UK government and may have contributed to its decision to impose and maintain the embargo. 43 As evidence, the main reason why the United Kingdom voted in favor of the UNSC resolution 182 (1963)-which called for an arms embargo against South Africa-was to reach a compromise with the African group at the United Nations, which was pressuring for sanctions (Konieczna 2019, 68). In 1970, the UK foreign secretary considered that resuming arms sales to South Africa could lead Zambia to cut copper exports and Nigeria to cut oil exports to the United Kingdom, which was one of the reasons why-he argued-the United Kingdom should not resume them. 44 A working party was created in 1970 to evaluate the consequences of resuming arms sales, concluding that a few countries-including Tanzania, Uganda, and Zambia-would probably leave the Commonwealth. 45 Although these potential reactions were considered by the UK government, the fact that Conservatives and Labour had different positions on the arms embargo indicates that pressures from African and Commonwealth countries were mediated by UK domestic politics. Besides, in 1970, Heath's government was unsure about whether potential retaliation from other African countries was worse than the costs of the embargo. His government also considered that a few major African countries (Kenya, Ghana, and Nigeria, for example) would not leave the Commonwealth if arms sales were resumed. The UK government also considered that keeping the embargo due to pressures from African countries might show weakness, thus damaging Britain's reputation. In addition, in 1977, Callaghan's government concluded that the embargo against South Africa had a more damaging impact on the United Kingdom than potential retaliation from other African countries. 46 This suggests that pressures from African and Commonwealth countries probably played a role, but perceived costs of imposing and maintaining the embargo were as large as-or larger than-the costs of not doing it. In any case, focusing only on the direct pressures from African and Commonwealth governments on the United Kingdom is misleading because their indirect influence was strong. Anti-apartheid policies from African and Commonwealth governments were an integral part of the transnational anti-apartheid struggle, being therefore endogenous to the transnational anti-apartheid movement. In this way, they constituted the British AAM, which had a central role in shaping the UK government behavior toward South Africa. Second, the United Kingdom might have imposed the embargo due to the UNSC resolutions approved in 1963 and 1964 that called for an arms embargo against South Africa. Yet, archival evidence indicates that the UK government would not have imposed an embargo had the Conservatives won the 1964 general election, indicating that domestic politics was a major determinant. Later, the UNSC resolution 418 (1977) imposed a mandatory embargo on South Africa. This resolution made the existing UK embargo less likely to be reversed because doing it would imply a violation of international law. Furthermore, the UK government prohibited exports of spare parts for military equipment in 1977 in order to comply with the UNSC resolution 418, indicating that this resolution influenced the UK policy toward South Africa. 47 Yet, Thatcher's government sought to adopt a less strict interpretation of the UNSC 1977 embargo than the previous Labour government, suggesting that domestic political dynamics also played a role. Furthermore, other countries had a less strict interpretation of the embargo than the United Kingdom: France and Israel, for example, continued supplying military equipment to South Africa. Breaching the embargo was possible because of loopholes in the UNSC resolution 418 and because the Arms Embargo Committee-in charge of enforcing it-proved to be weak (Konieczna 2019, 79). Moreover, UNSC resolutions were not exogenous to the UK position toward South Africa: the United Kingdom abstained in its vote on the UNSC resolution 181 (1963), but voted in favor of the subsequent UNSC resolutions that called for-or imposed-a multilateral arms embargo.
Third, the embargo might have been imposed because the UK "national interest" was changing. This potential explanation is drawn from Klotz (1995Klotz ( , 1999, who argued that an emerging norm in the United States about responsibility toward South Africa and a forged link with racial equality issues "reconstituted the US national interest." However, the case of the United Kingdom provides mixed evidence concerning a potential reconstituted national interest. In 1963, Harold Wilson affirmed that an arms embargo against South Africa would enable the United Kingdom to exert "moral leadership" and in this way influence other countries, which could be evidence for a reconstituted national interest. 48 Yet, it is not clear whether a national interest mindset determined Labour's decision to impose an embargo or was a "wrap" for a decision taken for other reasons. Barbara Castle was one of the main supporters of the embargo within the Labour Party, but there is no evidence that she thought about the embargo in terms of the UK national interest. In addition, although Conservatives did look at the issue of arms sales to South Africa from a national interest standpoint, they did it in traditional-rather than reconstitutedterms. They emphasized the security and economic benefits of exporting weapons to South Africa and argued-especially before the embargo was imposed-that an arms embargo damaged rather than promoted the UK national interest. Fourth, the emergence of norms concerning human rights might have contributed to the imposition and/or maintenance of the UK embargo. According to Klotz (1995Klotz ( , 1999, human rights norms-alongside the democratization wave of the 1970s-1980s-strengthened the anti-apartheid struggle, leading to a set of economic sanctions against South Africa in the 1980s. However, the transnational anti-apartheid struggle preceded an international human rights network and a solid international human rights regime, which emerged between the late 1960s and early 1980s (Keck and Sikkink 1998;Ropp and Sikkink 1999). In this way, they might have strengthened the transnational dimension of the anti-apartheid struggle, but cannot explain why the struggle became global in the first place. Moreover, a human rights frame was used only occasionally by anti-apartheid activists in Britain: their focus was on liberation, "taking power," democracy, anti-racism, and African nationalism, even if this implied supporting groups that defended the armed struggle, which was considered legitimate under certain circumstances and had been successful in Angola, Mozambique, and Zimbabwe. 49 Support to liberation was observed, for example, when activists emphasized that British weapons were-or would be-used by South Africa to prevent Namibia's independence and undermine liberation movements (and later independent governments) in neighboring countries. 50 As additional evidence of a lesser role for human rights-centered campaigns, Amnesty International's involvement in the anti-apartheid struggle was constrained by the fact that major opposition groups in South Africa defended the armed struggle. In 1964, Amnesty International removed Nelson Mandela from the list of prisoners of conscience because he was a cofounder of Umkhonto we Sizwe and considered armed resistance legitimate (Amnesty International 1978;Amnesty International UK 2020). The human rights language was nonetheless instrumentally useful to expand the diversity of anti-apartheid supporters and was an important reference point in debates and resolutions about the apartheid at the United Nations (Irwin 2012).

Conclusions
This article explored potential determinants of arms export behavior-and of sanctions in general-through a case study of an arms embargo imposed by the United Kingdom against South Africa in 1964 and maintained until the end of the white minority rule. The embargo was imposed and maintained despite the fact that South Africa played an important role in the struggle against Soviet influence in Southern Africa, was close to or surrounded British territories, and there was a bilateral agreement concerning the Simonstown Naval Base. Moreover, arms exports were one of the few power resources that Britain maintained in a context of imperial decline, being important to keep its military industry viable and increase or maintain leverage on other countries' policies. Also, the United Kingdom imposed this embargo, but other major Western arms exporters did not or did it later, in this way opening part of the South African arms market to competitors. The existence of a transnational anti-apartheid struggle explains in part why the United Kingdom imposed an embargo, but it is insufficient to explain why the UK government imposed it at that moment and why other governments did not impose it-or did it later. This paper argues that the United Kingdom imposed and maintained this embargo due in part to activities from a domestic advocacy network-whose hub was the AAM. The AAM-and other groups and individuals around it-contributed to internalize and translate the transnational anti-apartheid struggle into British domestic politics, turning arms exports to South Africa into a politically salient and contested issue in the United Kingdom. In this way, the AAM-led advocacy network mediated the influence of the transnational anti-apartheid struggle on the UK government. This process was facilitated by an international and domestic norm environment in which the existence of colonies and white minority governments was no longer appropriate. In that context, selling arms to South Africa was perceived as contributing to reproduce a colonial legacy, being thus incompatible with a postcolonial norm environment. Pressures on the UK government not to sell weapons to South Africa frequently adopted this frame. Yet, the appropriateness of selling weapons to South Africa was contested both before and after the embargo was imposed. After the embargo, Conservatives-and a few Labour leaders-contested its application, arguing that certain weapons for external defense should have their exports authorized. Exporting naval equipment, for example, was considered appropriate by some as they could not be used for domestic repression. However, such contestation reinforced the norm's robustness and clarified its scope: selling any type of weapon to South Africa-except those based on contracts signed before the 1964 UK embargo-was largely seen as inappropriate, regardless of whether they were for external defense or domestic use. Therefore, a norm-driven campaign was able to influence arms export behavior even in a context in which the UK-South Africa relations were geostrategically important and when a Cold War mindset was pervasive. Besides, this case study reveals how decolonization and postcolonial norms interacted with Cold War dynamics: the British government had incentives to adopt an anti-communist stance concerning arms sales on the one hand, but there were normative pressures regarding its role in a postimperial world on the other.
In addition to providing a comprehensive explanation of an important case in the history of British foreign policy, the anti-colonial struggle, and the Cold War, this paper contributes to a better understanding of a few theoretical issues. First, it demonstrates that governments can impose arms export restrictions unilaterally due to norm-driven pressures from advocacy networks, even when there are important strategic and economic interests at stake. In contrast, campaigns for economic sanctions are less likely to mobilize a large number of supporters and in this way less likely to influence government policies.
Second, concerning the interactions between local and global activism, the article indicates that a transnational movement can induce policy change, but the extent and scope of such change depends on whether and how domestic networks articulate and translate a transnational issue through and into domestic politics. If an issue is framed in a way that resonates with domestic audiences, major domestic political forces are more likely to support it or contest it, in this way mediating the influence of transnational movements on government behavior.
Third, concerning relations between party politics and foreign policy decisions. The likelihood of normative pressures influencing a government policy may depend on whether-and how-established political parties promote or contest them. The United Kingdom imposed an arms embargo in 1964 because the Labour Party defended and promoted a norm of responsibility concerning arms sales to South Africa. This reinforces findings of previous research showing that right-wing parties are more "hawkish" than left-wing ones: Conservatives were more willing to play power politics and arm South Africa than Labour. Yet, Conservatives were at the same time constrained by an international and domestic environment in which supporting South Africa violated shared norms and understandings concerning decolonization and racial equality.
Fourth, this study demonstrates how a changing norm environment shaped foreign policy. In a context of decolonization and postcolonial norms, providing weapons that maintained colonial domination or reproduced colonial legacies was largely considered inappropriate. The international and domestic normative environment therefore constrained the UK government's foreign policy, pushing it to adapt to a postcolonial world and limiting its ability to play power politics in Southern Africa.
Fifth, this article's findings indicate the dynamics and potential effects of norm contestation. After the embargo was imposed in 1964, contestation remained, but usually limited to whether weapons for external defense should be exported. Contestation not only revealed the existence of a strong opposition to the resumption of arms sales, but also contributed to reinforce the inappropriateness of selling arms to South Africa and clarify the range of cases on which the embargo should be applied. This reinforces findings of previous research about the potential effects of applicatory norm contestation, indicating that contestation can reinforce a norm's robustness.
Sixth, this paper indicates that a government not necessarily imposes sanctions to placate domestic or international pressures. As explored in this paper, the embargo was not a strategy of Labour governments to show to domestic or international audiences that the government was "doing something" against the apartheid. Rather, adopting the embargo was in line with understandings about the inappropriateness of selling weapons to the apartheid, which the Labour Party shared with other groups in the United Kingdom and elsewhere.