U.S. Policy in the Wake of 9/11: Hamdan v. Rumsfeld
This landmark 2006 Supreme Court case challenged the authority of the president to create military commissions without consulting Congress.
Salim Hamdan was captured by Afghan forces in 2001 and imprisoned at the detention center in Guantánamo Bay by the U.S. military for his employment as the driver of Osama bin Laden. According to the Oyez Project, Hamdan filed a petition for a writ of habeas corpus in federal district court to challenge his detention. However, before the district court had ruled on the petition, he received a hearing from a military tribunal and was designated an "enemy combatant."
The Circuit Court of Appeals for the District of Columbia found that the Geneva Convention could not be enforced in federal court and that the establishment of military tribunals had been authorized by Congress and was therefore not unconstitutional.
The Supreme Court, in a 5-to-3 decision authored by Justice John Paul Stevens, held that the president's creation of this sort of military commission was unconstitutional and failed to comply with the ordinary laws of the United States and the laws of war. According to the Oyez Project, the Geneva Convention, as a part of the ordinary laws of war, could therefore be enforced by the Supreme Court, along with the statutory Uniform Code of Military Justice. Hamdan's trial was, therefore, deemed illegal.
The Military Commissions Act of 2006 was passed by Congress in response to the Supreme Court's ruling. The act authorized the use of military commissions established by executive order and also created new legal precepts, including the concept that material support for terrorism was itself a war crime.
Source
» Oyez: U.S. Supreme Court Media. "Hamdan v. Rumsfeld."