This article addresses the pressing issue of what process courts should use to identify those questions whose resolution lies beyond their appropriate capacity and legitimacy. The search for such a process is a basic constitutional problem that has defied a clear answer for well over a hundred years. The chequered history of earlier attempts illustrates why commentators have once again begun to gravitate towards institutional approaches. The general features of institutional approaches include emphasis on uncertainty, judicial fallibility, systemic impact, collaboration between branches of government and incrementalism in judging. These features, however, are relied upon in support of two conflicting views of the role of judges in public law adjudication. One is restrictive, and advocates sharp limitations to the ambit of judicial review. The other is contextual, and, in stark contrast, it proposes to expand the ambit of review in reliance on the idea of using principles of restraint to structure the exercise of judicial discretion. While this article does not take sides between them, it nonetheless seeks to refine the contextual institutional approach by outlining a general framework for reasoning with principles of restraint, and by addressing some of the key difficulties such a reasoning process would face.