The Guantanamo military commissions were established by President George W. Bush – through a military order – on November 13, 2001, to try certain non-citizen terrorism suspects at the Guantanamo Bay prison. To date, there have been a total of eight convictions in the military commissions, six through plea agreements with the defendants. Several of the eight convictions have been overturned in whole or in part on appeal, mostly by U.S. federal courts. There are five cases currently ongoing in the commissions—and another two pending appeal—including United States v. Khalid Sheikh Mohammed, et al.—the prosecution of the detainees alleged to be most responsible for the September 11, 2001, attacks. None of those five cases has yet gone to trial. History As explained by the Congressional Research Service, the United States first used military commissions to try enemy belligerents accused of war crimes during the occupation in Mexico in 1847, made use of them in the Civil War and in the Philippine Insurrection, and then again in the aftermath of World War II. For the next fifty years, the U.S. relied on its established federal court and military justice systems to prosecute alleged war crimes and terrorism offenses. On November 13, 2001, President Bush issued a military order governing the "Detention, Treatment, and Trial of Certain Non-Citizens in the War Against Terrorism". The military order effectively established the novel military commissions at Guantanamo Bay, which began in 2004 with charges against four Guantanamo detainees. In 2006, the Supreme Court struck down the military commissions (in Hamdan v. Rumsfeld), determining that the commissions violated both the Uniform Code of Military Justice and the 1949 Geneva Conventions. In response, and in order to permit the commissions to go forward, Congress passed the Military Commissions Act of 2006 (MCA). Congress significantly amended the MCA in 2009. In 2019, exercising authority granted to him under the MCA, the Secretary of Defense published an updated Manual for Military Commissions, which sets forth the current procedures that govern the commissions. Costs According to the United States Government Accountability Office (GAO), from fiscal years 2012 to 2018 the Department of Defense spent $679.6 million on the military commissions. Defense Department officials told GAO that the department plans to spend almost $1.0 billion more from fiscal year 2019 through at least fiscal year 2023. Commission cases and status Of the 779 men detained at Guantanamo at some point since