What is the UCMJ?

What is the Uniform Code of Military Justice (UCMJ), and why should you care? If you’re reading this, you’re probably in the military or know someone who is. The UCMJ is the criminal code that applies to people in the military. It’s basically an extra set of criminal laws that apply in addition to whatever criminal laws you’re already living under.

For example, if you live in Colorado, you need to follow both Colorado state law and the laws of the United States (federal law). Depending on what crime you commit in Colorado, that crime could violate state law, federal law, or both. If you’re in the military, then committing a crime may also violate the UCMJ.



So how do you know when a state court, federal court, or military court-martial can prosecute a crime? It all comes down to jurisdiction. A court has to have both personal and subject matter jurisdiction to prosecute someone for committing a crime.

Personal jurisdiction means that the defendant falls under the authority of the court trying the case. In a state court, that generally means that the defendant committed a crime within that state’s borders. In federal court, that means the defendant committed a crime within the United States.


The UCMJ is slightly different: it applies to military members at all times and in all places. If you are on active duty, a member of the Reserves or Guard on certain orders, a Cadet/Midshipman, or if you fall into certain other categories listed in Article 2 of the UCMJ, then a Court-Martial has personal jurisdiction over you and you can be prosecuted for violations of the UCMJ that you commit while in that status.


Subject matter jurisdiction simply means that the court has the authority to prosecute the matter at issue in the case. For a Colorado state court to prosecute a case, the defendant must have violated Colorado criminal law. The same goes for federal courts. A court-martial has subject matter jurisdiction solely over violations of the UCMJ.


Double (or Triple?) Jeopardy

There are some crimes under the UCMJ that are “uniquely military” crimes, such as going AWOL (absent without leave), disrespecting a superior commissioned officer, and failing to obey a lawful order or regulation. State and federal courts do not have subject-matter jurisdiction over those offenses, so they can only be prosecuted by a military court-martial.

Most crimes prosecuted by the military, however, are not unique to the military. Think domestic violence, larceny (theft), sexual assault, arson, burglary, assault…you get the idea. Those are all crimes under the UCMJ, as well as under state law, federal law, or both. So what happens when a military member commits a crime under the UCMJ, but another court also has jurisdiction? Can they both prosecute?


The answer depends on whether the “other” court is a federal or state court. A court-martial and a federal court–since they are both federal courts–cannot both prosecute the same person for the same crime because that would violate the double jeopardy clause of the Fifth Amendment to the United States Constitution. A court-martial and a state court, however, are courts of different governments–federal vs. state–so double jeopardy does not prohibit double prosecution in that scenario.


So what happens when a military member violates the UCMJ and state law at the same time? Typically, the state investigators and prosecutors have a working relationship with the military investigators and prosecutors, and they end up agreeing which one of them will prosecute the case.


Although having a “double prosecution” would not technically violate the Fifth Amendment, the military has a general rule to not prosecute the same crimes that a state does unless the Secretary of that military branch gives approval. This does not happen often. The vast majority of the time, even when a crime violates both state law and the UCMJ, the defendant will only be prosecuted once.


Extra Reading

Want to read the UCMJ yourself and see what crimes are in it? Click here to view or download the pdf. The punitive Articles (listing all the crimes) start with Article 77.