The U.S. Court of Appeals for the District of Columbia Circuit concluded that providing support for terrorism was not a war crime at the time of Hamdan's alleged conduct from 1996 to 2001 and therefore could not support a conviction.

Human rights activists hailed the ruling as a blow to the legitimacy of the U.S. military commission system.

Hamdan was captured at a roadblock in Afghanistan in November 2001, not long after the U.S. invasion of that country following the September 11 attacks on the United States.