In the United States, the laws of court-martial are set forth in the Uniform Code of Military Justice.
The plural form of this word is courts-martial.
Summary Court-Martial - The least serious court-martial. It consists of one commissioned officer. These proceedings can result in no sentence in excess of one month's confinement or forfeiture of two-thirds of one month's pay.
The convening officer in any case appoints other officers or enlisted personnel under his command to sit on the court, determine the verdict, and decide upon punishment when necessary.
Some crimes worthy of court-martial are robbery, murder, drug abuse, absence without official leave, sodomy, perjury, rape, assault, forgery, and disrespect to a superior officer.
"Each armed force (branch of the military) has court-martial jurisdiction over all persons subject to this chapter. The exercise of jurisdiction by one armed force over personnel of another armed force shall be in accordance with regulations prescribed by the President." (UCMJ)
Who can sit on a court-martial (from UCMJ):
-"Any commissioned officer on active duty is eligible to serve on all courts-martial for the trial of any person who may lawfully be brought before such courts for trial."
-"Any warrant officer on active duty is eligible to serve on general and special courts-martial for the trial of any person, other than a commissioned officer, who may lawfully be brought before such courts for trial."
-"Any enlisted member of an armed force on active duty who is not a member of the same unit as the accused is eligible to serve on general and special courts-martial for the trial of any enlisted member of an armed force who may lawfully be brought before such courts for trial, but he shall serve as a member of a court only if, before the conclusion of a session called by the military judge under section 839(a) of this title (article 39(a)) prior to trial or, in the absence of such a session, before the court is assembled for the trial of the accused, the accused personally has requested orally on the record or in writing that enlisted members serve on it. After such a request, the accused may not be tried by a general or special courts-martial the membership of which does not include enlisted members in a number comprising at least one-third of the total membership of the court, unless eligible enlisted members cannot be obtained on account of physical conditions or military exigencies. If such members cannot be obtained, the court may be assembled and the trial held without them, but the convening authority shall make a detailed written statement, to be appended to the record, stating why they could not be obtained."