A more thorough explanation:

Military Law is a set of rules and regulations that govern the behavior of members of the armed forces. It is different from civilian law because military personnel are held to a higher standard of conduct due to the nature of their job. The Uniform Code of Military Justice (UCMJ) is the legal system that applies to all branches of the military.

For example, if a member of the military commits a crime, they can be punished under both civilian law and military law. Punishments for violating military law can range from losing privileges to being discharged from the military.

The UCMJ covers offenses specific to military officials, such as abuse of authority and dereliction of duty, as well as ordinary civilian crimes. However, the standard of proof and punishments are different from civilian courts.

The origins of military law can be traced back to the United States Constitution, which authorized the establishment of a justice system within the military. Congress issued a new set of rules known as the Articles of War in 1806, and later the 1863 Lieber Code governed military justice. Finally, in 1951, Congress superseded the Articles of War and the Lieber Code with the Uniform Code of Military Justice.

The UCMJ is federal law and is located in Title 10 United States Code Chapter 47. Court-martial convictions can be appealed through military courts and the United States Court of Appeals of the Armed Forces (CAAF), which is a federal appellate court made up of five civilian judges appointed by the President. Decisions from the CAAF can be subjected to direct review by the United States Supreme Court.