A court-martial is a legal proceeding where courts try a member of the military for offenses against military law. Courts-martial are governed by the provisions of the Uniform Code of Military Justice (UCMJ), except as otherwise provided by statute. Prosecution of a general or special court-martial is in the name of the state. The three types of courts-martial are general courts-martial, special courts-martial, and summary courts-martial. Jurisdiction arises with the seriousness of the allowable penalty of UCMJ.
Jurisdiction:
A court-martial is a court of special and limited jurisdiction. The United States Supreme Court has held that courts-martial have no jurisdiction to try those who are not members of the armed forces, no matter how intimate the connection between their offense and the concerns of military discipline. There are three general prerequisites that must be met for courts-martial jurisdiction to vest (1) jurisdiction over the offense, (2) personal jurisdiction over the accused, and (3) a properly convened and composed court-martial. UCMJ and the Rules for Courts-Martial specify who may convene a court-martial.
General Courts-Martial:
General courts-martial have jurisdiction to try persons subject to the UCMJ for any offense made punishable by the Code. General Courts-Martial consist of a military judge and no fewer than five members (jurors), or only a military judge if before the court is assembled the accused, knowing the identity of the military judge and after consultation with defense counsel, requests in writing a court composed of only a military judge and that judge approves. General courts-martial can adjudge punishment ranging from a dishonorable discharge to life imprisonment or death by lethal injection.
Special Courts-Martial:
Special courts-martial have jurisdiction to try persons subject to the UCMJ for any noncapital offense made punishable by the Code and, under such regulations as the President may prescribe, for capital offenses. Special courts-martial, consisting of no fewer than three members, or a military judge and no fewer than three members, or only a military judge, if one has been detailed to the court, and the accused under the same conditions as those for general courts-martial so requests. Special courts-martial can adjudge incarceration up to six months.
Summary Courts-Martial:
Summary courts-martial have jurisdiction to try persons subject to the UCMJ, except officers, cadets, aviation cadets, and midshipmen, for any noncapital offense made punishable by the Code. Summary Courts-Martial consist of one commissioned officer. Summary courts-martial may not adjudge the more serious punishments, being limited to the imposition of no more than one month's confinement, and counsel is seldom involved.
Counsels:
The accused has the right to be represented in his or her defense before a general or special court-martial by civilian counsel if provided by the accused, or by military counsel of his or her own selection if reasonably available, as well as by the military defense counsel detailed under Article 27. All military defense counsel are licensed attorneys who have received specialized training in military law.
See e.g.; Hamdan v. Rumsfeld, 548 U.S. 557 (2006)
[Last updated in September of 2022 by the Wex Definitions Team]