In 2001, Congress passed the Authorization for Use of Military Force (AUMF), 115 Stat. 224 (2001), which authorized the president to “use all necessary and appropriate force” against organizations and persons he determined were involved with the September 11, 2001 terrorist attacks. In 2006 and 2009, Congress also implemented the Military Commission Acts (MCAs), Pub. L. No. 109-366, 120 Stat. 2600, Pub. L. No. 111-84, 123 Stat. 2190, which addressed who could be detained under the AUMF, providing definitions of “unlawful enemy combatants” and “unprivileged enemy belligerents.” Ghaleb Nassar Al-Bihani (defendant) was a Yemeni citizen who defended the Taliban against the Northern Alliance in Afghanistan. Al-Bihani served as a cook and carried a weapon for a group allied with the Taliban known as the 55th Arab Brigade (55th), which fought against the Northern Alliance. Al-Bihani and the rest of the brigade eventually surrendered to Northern Alliance forces. Al-Bihani was handed over to the United States in 2002 and sent to Guantanamo Bay for detention and interrogation, pursuant to the AUMF. Al-Bihani unsuccessfully petitioned for a writ of habeas corpus and appealed.