A military tribunal is a kind of military court designed to try members of enemy forces during wartime, operating outside the scope of conventional criminal and civil proceedings. The judges are military officers and fulfill the role of jurors. Military tribunals are distinct from courts-martial.
A military tribunal is an inquisitorial system based on charges brought by a military authority, prosecuted by a military authority, judged by military officers, and sentenced by military officers against a member of an adversarial force.
General George Washington used military tribunals during the American Revolution. Commissions were also used by General (and later President) Andrew Jackson during the War of 1812 to try a British spy; commissions, labeled "Councils of War," were also used in the Mexican-American War.
The Union used military tribunals during and in the immediate aftermath of the American Civil War. Military tribunals were used to try Native Americans who fought the United States during the Indian Wars which occurred during the Civil War; the thirty-eight people who were executed after the Dakota War of 1862 were sentenced by a military tribunal. The so-called Lincoln conspirators were also tried by military commission in the spring and summer of 1865. The most prominent civilians tried in this way were Democratic politicians Clement L. Vallandigham, Lambdin P. Milligan, and Benjamin Gwynn Harris. All were convicted, and Harris was expelled from the Congress as a result. It must be noted that all of these tribunals were concluded prior to the Supreme Court's decision in Milligan.
The use of military tribunals in cases of civilians was often controversial, as tribunals represented a form of justice alien to the common law, which governs criminal justice in the United States, and provides for trial by jury, the presumption of innocence, forbids secret evidence, and provides for public proceedings. Critics of the Civil War military tribunals charged that they had become a political weapon, for which the accused had no legal recourse to the regularly constituted courts, and no recourse whatsoever except through an appeal to the President. The U. S. Supreme Court agreed, and unanimously ruled that military tribunals used to try civilians in any jurisdiction where the civil courts were functioning were unconstitutional, with its decision in Ex Parte Milligan, 71 U.S. 2 (1866).
Military commissions were also used in the Philippines in the aftermath of the Spanish-American War; as these were used in an active war zone as an expedient of war, they did not fall afoul of Milligan.
President Franklin D. Roosevelt ordered military tribunals for eight German prisoners accused of planning sabotage in the United States as part of Operation Pastorius. Roosevelt's decision was challenged, but upheld, in Ex parte Quirin. All eight of the accused were convicted and sentenced to death. Six were executed by electric chair at the District of Columbia jail on August 8, 1942. Two who had given evidence against the others had their sentences reduced by Roosevelt to prison terms. In 1948, they were released and deported to the American Zone of occupied Germany.
Most recently, as discussed below, the administration of George W. Bush has sought to use military tribunals to try "unlawful enemy combatants", mostly individuals captured abroad and held at a prison camp at a military base at Guantánamo Bay, Cuba.
Courts-martial generally take jurisdiction only over members of their own military and sometimes, civilians present with them. Even when court-martial procedures are used to try enemies, the body convened is often instead called a military tribunal or military commission.
A military tribunal or military commission, in contrast, is generally used to refer to bodies who assert jurisdiction over persons who are held in military custody and stand accused of being enemies in a conflict in which the military is engaged who a combatants who have violated a law of war.
Military tribunals convened to impose punishment (as opposed to tribunals established solely to classify persons in military custody as combatants or non-combatants), generally limit themselves to accusations that an individual violated the laws of war. Military tribunals generally do not consider cases where an individual is merely being accused of being a combatant on behalf of the enemy.
Military tribunals also, generally speaking, do not assert jurisdiction over people who are acknowledged to be non-combatants who have committed ordinary civil crimes. But, military tribunals are sometimes used to try individuals not affiliated with a national military who are nonetheless accused of being combatants acting in violation of the laws of war.
While tribunals can provide for quick trials under the conditions of war, many critics say this occurs at the expense of justice.
Time constraints and the inability to obtain evidence can greatly hamper a case for the defense. Others have tried to use this argument in favor of commissions, as issues such as chain of evidence and hearsay, which are applied in civilian and criminal trials, could preclude conviction if such rules were applied (e.g., how to claim a bomb was in proper custody from a battlefield to a courtroom?) Civilian trials must be open to the public, while military tribunals can be held in secret. Because conviction usually relies on some sort of majority quota, the separability problem can easily cause the verdict to be displeasing not only to the defendant but also to the tribunal.
Decisions made by a military tribunal cannot be appealed to federal courts. The only way to appeal is a petition for a panel of review (which may or may not include civilians as well as military officers) to review decisions, however the President, as commander-in-chief, has final review of all appeals. No impartial arbiter is available.
Although such tribunals do not satisfy most protections and guarantees provided by the United States Bill of Rights, that has not stopped Presidents from using them, nor the U.S. Congress from authorizing them, as in the Military Commissions Act of 2006.
President George W. Bush ordered that certain detainees imprisoned at the Naval base at Guantanamo Bay were to be tried by military commissions. This decision sparked controversy and litigation. On June 29, 2006, the U.S. Supreme Court limited the power of the Bush administration to conduct military tribunals to suspected terrorists at Guantánamo Bay.
In December 2006, the Military Commissions Act of 2006 was passed and authorized the establishment of military commissions subject to certain requirements and with a designated system of appealing those decisions. A military commission system addressing objections identified by the U.S. Supreme Court was then established by the Department of Defense. Litigation concerning the establishment of this system is ongoing. As of June 13, 2007, the appellate body in this military commission system had not yet been constituted.
Three cases had been commenced in the new system, as of June 13, 2007. One detainee, David Matthew Hicks plea bargained and was sent to Australia to serve a nine-month sentence. Two cases were dismissed without prejudice because the tribunal believed that the men charged had not been properly determined to be persons within the commission's jurisdiction on June 4, 2007, and the military prosecutors asked the commission to reconsider that decision on June 8, 2007.  One of the dismissed cases involved Omar Ahmed Khadr, who was captured at age 15 in Afghanistan after having allegedly killed a U.S. soldier with a grenade. The other dismissed case involved Salim Ahmed Hamdan who is alleged to have been Osama bin Laden's driver and is the lead plaintiff in a key series of cases challenging the military commission system. The system is in limbo until the jurisdictional issues addressed in the early cases are resolved.