Personal Jurisdiction: Who Is Subject to the UCMJ

The day a recruit is sworn in, a second body of criminal law switches on over that person’s life, one that civilians never live under. The day someone leaves the service for good, that law usually switches off. But the line between in and out is not as clean as a discharge certificate suggests. A retiree drawing a pension, a reservist between drills, a cadet who has not yet finished a single year, a civilian contractor in a war zone: each sits somewhere on a spectrum of military authority, and where exactly they sit decides whether a court-martial can reach them at all. This is the question of personal jurisdiction, and it is governed by a single statute that rewards careful reading.

Personal jurisdiction is the who of court-martial authority. It is distinct from the what (which offenses a court-martial can try, a question answered by status under Solorio v. United States and the punitive articles, covered in the dedicated discussion of subject-matter jurisdiction) and from the where (the geographic reach of military authority, covered in the discussion of territorial jurisdiction). All of those other questions presuppose this one. Before any of them matters, a court-martial must have authority over the person. That authority comes from Article 2 of the Uniform Code of Military Justice, codified at 10 U.S.C. § 802.

What Article 2 actually does

Article 2 is a list. It does not describe a single class of “military personnel” and leave the edges to interpretation. Instead it enumerates specific categories of persons who are subject to the code, each with its own triggering condition. A person falls under court-martial jurisdiction if, and only if, that person fits one of the enumerated categories at the relevant time. This is why the analysis is rarely “is this person in the military” and almost always “which paragraph of Article 2 applies, and is its condition met right now.”

The categories below are the ones that govern the overwhelming majority of cases. Reading them as a who-is-in, who-is-out map is more useful than reading the statute straight through, because the same category can put a person in on Monday and out on Tuesday depending on a single fact.

Category (Article 2)	In the military's reach when	Out of reach when	The fact that flips it
Active-duty regular component, 2(a)(1)	On active duty, including the period awaiting discharge after an enlistment expires	Active service has been legally terminated and the person is fully separated	The legal end of active service, not merely the last duty day
Cadets, aviation cadets, midshipmen, 2(a)(2)	Enrolled at a service academy	Disenrolled or graduated and not yet commissioned into a covered status	Enrollment status at the academy
Reserve component, 2(a)(3)	During inactive-duty training (for example, weekend drill) or while on active-duty orders	Off orders and not in a training period, living as a civilian	Whether the person is currently on orders or in a drilling period
Retired regular component entitled to pay, 2(a)(4)	Retired from a regular component and receiving retired pay	Never qualified for or no longer entitled to retired pay	Entitlement to retired pay, the contested hinge
Retired reserve receiving hospitalization, 2(a)(5)	A reserve retiree receiving inpatient care from an armed force	Not receiving such care	The fact of armed-forces hospitalization
Fleet Reserve and Fleet Marine Corps Reserve, 2(a)(6)	A member of the Fleet Reserve or Fleet Marine Corps Reserve	Fully retired out of that status, where applicable	Membership in the Fleet Reserve, also contested
Prisoners serving a court-martial sentence, 2(a)(7)	In custody of an armed force serving a sentence	Sentence served and released, no other hook	Continued confinement under a court-martial sentence
Persons accompanying the force in the field, 2(a)(10)	In time of declared war or a contingency operation, serving with or accompanying an armed force in the field	Outside a declared war or contingency operation, or not in the field	The existence of a declared war or contingency operation
Geneva law-of-war violators, 2(a)(13)	Persons in defined Geneva categories who violate the law of war	Outside those categories	Status under the Geneva framework

A few of these reward a closer look, because they are where the real disputes live.

Active duty: the cleanest case, with one trap

For the regular active-duty member, jurisdiction is straightforward. From the moment of valid entry into active service, the member is subject to the code, and that authority continues through the entire enlistment, including the awkward window after a term of enlistment expires but before the paperwork of separation is complete. Article 2 expressly reaches members “awaiting discharge after expiration of their terms of enlistment.”

The trap is at the other end. Jurisdiction ends when active service is legally terminated, not on the day the member walks out the gate or stops reporting. The code addresses this through the concept of constructive enlistment in Article 2(c): a person who voluntarily submitted to military authority, met the basic enlistment qualifications, received military pay, and performed military duties is treated as subject to the code until active service is terminated in accordance with law, even if some technical defect tainted the original enlistment. The jurisdictional clock runs on legal status, and an attempt to argue out of court-martial reach by pointing to a defective enlistment or an expired contract usually fails.

Reservists: in and out, sometimes within the same weekend

Reserve and National Guard members are the clearest illustration that Article 2 is about condition, not identity. A reservist is not subject to the code at all times. The reservist comes under court-martial jurisdiction when serving on federal active-duty orders or during inactive-duty training, the weekend drill being the typical example, and falls back out when the training period ends and the member returns to civilian life. Misconduct committed during a drill weekend can be reachable; the identical conduct committed the following Wednesday, off orders, generally is not. National Guard members add a further wrinkle, because Guard members ordinarily serve under state authority and come under the federal UCMJ only when called or ordered into federal service.

Cadets and midshipmen: subject from day one

Cadets, aviation cadets, and midshipmen at the service academies are subject to the UCMJ by their own dedicated category in Article 2(a)(2), even though they are not yet commissioned officers and may not have completed any operational service. Enrollment at the academy is itself the qualifying status. This is one of the cleaner categories: the relevant question is simply whether the person is currently enrolled.

Retirees and the Fleet Reserve: the genuinely unsettled frontier

The most contested area of personal jurisdiction is the one most service members assume is settled. Retired members of a regular component who are entitled to retired pay remain subject to the UCMJ under Article 2(a)(4), and members of the Fleet Reserve and Fleet Marine Corps Reserve remain subject under Article 2(a)(6). On its face, this means a retiree drawing a pension can, in principle, be court-martialed for an offense committed years into retirement.

That proposition has been challenged, and the challenge is live. In United States v. Begani, the Court of Appeals for the Armed Forces held that retired members, including Fleet Reservists, are part of the “land and naval Forces” within the meaning of the Constitution and may be court-martialed, and the Supreme Court declined to review that decision. But in the related litigation surrounding Larrabee v. United States, a federal district court in the District of Columbia found the application of Article 2(a)(6) to a retiree unconstitutional, the first such ruling in the code’s history, before the D.C. Circuit reversed and upheld the jurisdiction in 2022, with the Supreme Court again declining review. As matters stand, the statute is on the books and courts-martial of qualifying retirees have been upheld, but a serious constitutional question about whether and when a retiree retains a sufficient current connection to the armed forces remains unresolved at the highest level. This is the rare corner of military law where the honest answer to “can a retiree be court-martialed” is “currently yes, but the question is being actively contested.” (Status as of mid-2026.)

The hard outer boundary: the discharged civilian

The clearest limit on personal jurisdiction is the person who has been completely and lawfully discharged, with no remaining military relationship. The Supreme Court drew that line in United States ex rel. Toth v. Quarles, 350 U.S. 11 (1955). Toth had been honorably discharged from the Air Force and was working a civilian job when military authorities arrested him for a murder allegedly committed during his earlier service in Korea. The Court held he could not be court-martialed. An ex-service member with no relationship of any kind to the military is a civilian, entitled to the protections of an Article III court, and Congress’s power to make rules for the armed forces does not stretch to reach him. Toth marks the floor: once a person is genuinely out, with no Article 2 category still attaching, a past offense in uniform does not pull that person back into a military courtroom. The contrast with the retiree categories is precisely the point. A retiree drawing pay is, by statute, still connected; the fully discharged civilian is not.

Civilians accompanying the force

A narrow but important category reaches certain civilians. Under Article 2(a)(10), in time of declared war or a contingency operation, persons serving with or accompanying an armed force in the field are subject to the code. This is how contractors and other civilian personnel in a combat theater can, in defined circumstances, fall under court-martial jurisdiction. The triggering condition is demanding: there must be a declared war or a qualifying contingency operation, and the person must be serving with or accompanying the force in the field. Outside those conditions, the category does not apply, and the exercise of this authority over civilians has its own constitutional sensitivities that keep it narrow in practice. Overseas, jurisdiction over both service members and accompanying civilians is further shaped by status-of-forces arrangements with the host nation, a subject addressed in the discussion of overseas jurisdiction.

How to read a personal-jurisdiction question

The recurring mistake is to ask whether someone “is military.” Article 2 does not work that way. The disciplined approach is three steps.

Identify the candidate category. Which paragraph of Article 2 might apply: active duty, reserve, retired regular, Fleet Reserve, cadet, accompanying civilian, and so on.
Test its condition at the relevant time. Was the triggering fact present when the offense occurred and, where it matters, when jurisdiction is being exercised? A reservist must have been on orders or in training; an accompanying civilian must have been in the field during a declared war or contingency operation.
Check for an exit. Has the status legally ended? A discharged member with no remaining category is outside the code under Toth; a member awaiting discharge or covered by constructive enlistment is still inside.

Run those three steps and almost every personal-jurisdiction question resolves, including the ones that feel counterintuitive, like the drilling reservist who is reachable on Saturday and not on Wednesday, or the retiree who is statutorily reachable but constitutionally contested.

Frequently asked questions

Is a service member subject to the UCMJ twenty-four hours a day?
For active-duty regular members, effectively yes; jurisdiction attaches to active-duty status and continues through the enlistment, including conduct off duty and off base. For reservists and Guard members, no; they are subject only during the periods Article 2 specifies, such as active-duty orders or inactive-duty training.

Can a retired service member be court-martialed?
Under Article 2, retired regular-component members entitled to retired pay, and members of the Fleet Reserve and Fleet Marine Corps Reserve, remain subject to the code, and such courts-martial have been upheld. Whether that is constitutional in all circumstances is the subject of ongoing litigation, with appellate courts so far sustaining the jurisdiction while the broader question remains unsettled.

Can a person be court-martialed after a full discharge for something done in uniform?
Generally no. Under United States ex rel. Toth v. Quarles, a person who has been completely and lawfully discharged, with no remaining military relationship, is a civilian and cannot be court-martialed for offenses committed during prior service. The key is that no Article 2 category still attaches.

When can a civilian be tried by court-martial?
Only in narrow situations. The principal one is Article 2(a)(10): in time of declared war or a contingency operation, civilians serving with or accompanying an armed force in the field. The conditions are strict, and the exercise of military authority over civilians carries constitutional limits that keep it exceptional.

Does it matter where the offense was committed for personal jurisdiction?
For the question of authority over the person, no. Personal jurisdiction asks only whether the individual falls within an Article 2 category. Whether the offense is triable is a separate, status-based question answered by the doctrine on subject-matter jurisdiction, and geography is addressed by territorial jurisdiction.

Sources and Authorities

Uniform Code of Military Justice, Article 2 (10 U.S.C. § 802), persons subject to the code, including subsections (a)(1) active duty, (a)(2) cadets and midshipmen, (a)(3) reserve component on inactive-duty training, (a)(4) retired regulars entitled to pay, (a)(5) retired reserve receiving hospitalization, (a)(6) Fleet Reserve and Fleet Marine Corps Reserve, (a)(7) prisoners under sentence, (a)(10) persons accompanying the force in the field, (a)(13) Geneva law-of-war categories, and (c) constructive enlistment
United States ex rel. Toth v. Quarles, 350 U.S. 11 (1955) (no court-martial jurisdiction over a fully discharged ex-service member)
United States v. Begani, U.S. Court of Appeals for the Armed Forces (Fleet Reserve and retiree jurisdiction upheld; certiorari denied)
Larrabee v. United States litigation, D.C. Circuit (2022) (upholding Article 2(a)(6) jurisdiction after a contrary district-court ruling; certiorari denied)
U.S. Constitution, Article I, Section 8, Clause 14 (congressional power to govern and regulate the land and naval forces)

Disclaimer

This article explains, as general legal information, the categories of persons subject to the Uniform Code of Military Justice and the disputes at the edges of that authority. It is not legal advice and does not address any individual’s situation. Personal-jurisdiction questions, particularly those involving retirees, reservists, constructive enlistment, or civilians accompanying the force, turn on specific facts and an evolving body of case law that only a qualified military defense attorney can evaluate.