If you are an active duty service-member, a Guardsman on Title 10 orders, or a Reservist on orders, then you are subject to the UCMJ and court-martial jurisdiction for any crime you are alleged to have committed. It doesn't matter where the crime was committed, and double jeopardy does not bar a court-martial if a prior civilian court tried and convicted you of the same offense.
This rule is what a military defense lawyer should tell you about your personal jurisdiction for court-martial.
If you are in TDRL or PDRL status and receiving medical care from a military hospital, you are subject to court-martial jurisdiction under the UCMJ. The Court of Appeals for the Armed Forces (CAAF) and the Navy-Marine Corps Court of Criminal Appeals (NMCCA) have said this. The Supreme Court has not decided the jurisdictional question. See my article on this here.
If you are in the Navy or Marine Corps Fleet Reserve, you are--currently--subject to court-martial for offenses after or before transfer. This part of the UCMJ is being challenged in federal court in three cases: Begani, Larrabee, and Dinger. See my article published here.
If you are in a retired status, your military defense counsel should be or should get familiar with the special rules applied to retirees.
If you are a regular component retiree, you are subject to court-martial for offenses committed before retirement (even if not discovered until after retirement) and for offenses after retirement.
If you are a Retired Reserve you are not subject to the UCMJ and court-martial. See my article about LtCol Brock in the USNI Proceedings, here.
Article 2, UCMJ
, sets out a long list of people in and out of uniform who are subject to the UCMJ and who could then face court-martial for misconduct.
- Active duty.
- Reserves on orders.
- Guardsmen on Title 10 orders (note here that they may be subject to their own state "UCMJ" when not federalized).
- Prisoners, regardless of their having received a DD 214.
- Cadets and Midshipmen.
- Certain civilians "In time of declared war or a contingency operation, persons serving with or accompanying an armed force in the field."
- NOAA and USPHS in certain circumstances.
- Enemy POWs.