High Quality Content by WIKIPEDIA articles! Courts-martial in the United States are criminal trials conducted by the U.S. military. Most commonly, courts-martial are convened to try members of the U.S. military for violations of the Uniform Code of Military Justice (or UCMJ), which is the U.S. military`s criminal code. However, they can also be convened for other purposes, including military tribunals and the enforcement of martial law in an occupied territory. Courts-martial are governed by the rules of procedure and evidence laid out in the Manual for Courts-Martial, which contains the Rules for Courts-Martial, Military Rules of Evidence, and other guidance.