This casenote outlines and analyses the US Supreme Court's 2006 decision in Hamdan v. Rumsfeld. In this case the Court held that suspected terrorists held in Guantánamo Bay were entitled to bring habeas corpus petitions to federal courts and to the benefits of the Uniform Code of Military Justice and Common Article 3 of the Geneva Conventions. The US Supreme Court eschewed the tradition of judicial deference to overturn the President's determination that military commissions could be established without congressional approval in the circumstances of the ‘War on Terrorism’. The casenote goes on to consider the aftermath of this decision, including the introduction of the Military Commissions Act 2006, and the implications of this Act for the future of Guantánamo Bay litigation.