On 29 June 2006 the United States Supreme Court issued a landmark opinion in the case of Hamdan v. Rumsfeld. The Court's essential holding, joined by five justices, found that the President lacked the authority to establish the military commissions which he had created by special order on 13 November 2001. The holding dealt the administration of George W. Bush a stunning defeat, and the very fact of the Court's striking down the military commissions confirmed an assertive, if slim, majority on the court in a time of national emergency and armed conflict. Most striking, the Court found that the so-called war on terror is governed by common Article 3 of the Geneva Conventions of 1949, a legal conclusion that, because of the legitimacy and prestige of the Court, neither Congress nor the President may easily avoid. The lasting jurisprudential impact of the decision, however, remains to be seen. For, on the one hand, Hamdan suggests that the military commissions simply lacked the authority conferred by a statute of Congress – and Congress has since remedied that gap. But, on the other hand, what impact will the Court's analysis of the laws of war have on the Commissions and future judicial assessments of their lawfulness?

This essay examines the international legal contours of Hamdan. It does so as follows: First, it gives the background to the key legal decisions made in 2001 and 2002 to establish the military commissions and interpret the Geneva Conventions so as not to apply to Taliban and Al Qaeda detainees. Second, we explore the principal international legal elements of Hamdan. Third, we conclude with an epilogue of sorts, noting the aftermath of Hamdan in the Military Commissions Act of 2006 and reflecting on a few key points raised – and left unanswered – by Hamdan v. Rumsfeld.