“Armies are equipped and trained to vanquish enemies. If turned inward, they can easily become an instrument of tyranny.”
—Elizabeth Goitein, Senior Director for Liberty & National Security, Brennan Center for Justice
The United States has long drawn a bright line between military power and civilian law enforcement. The Posse Comitatus Act (PCA) embodies that line, reflecting a deep constitutional instinct: armed forces are not to be used to govern civilians at home. Recent efforts to assign active‑duty military lawyers—Judge Advocate General (JAG) officers—to serve as immigration judges within the Department of Justice (DOJ) press directly against that boundary.
This essay argues that detailing armed forces judge advocates to adjudicate immigration cases violates the PCA. It explains why immigration adjudication is inseparable from law enforcement, why the DOJ’s contrary legal opinion rests on a formalistic and ultimately unconvincing distinction, and why using “soldiers in robes” in civilian courts undermines both the statute and the civil‑military norms it was designed to protect.
The Posse Comitatus Act and its core purpose
The PCA, enacted in 1878, makes it a crime to use the Army or Air Force “as a posse comitatus or otherwise to execute the laws” except where expressly authorized by Congress. Its purpose is not technical; it is fundamentally about keeping the military out of domestic law enforcement and preventing the armed forces from exercising coercive authority over civilians on US soil.
Over time, Congress and the courts have treated the PCA as a structural safeguard of democracy, not a mere procedural rule. It reflects a basic principle of American constitutionalism: civilian agencies enforce and adjudicate the law; the military defends the nation from external threats. When those roles blur, the risk is not only legal overreach, but also erosion of public trust and the normalization of military involvement in civilian governance.
Immigration adjudication as law enforcement
Immigration courts are not abstract tribunals operating in a vacuum. They are embedded within the Department of Justice and function as a critical component of the federal immigration enforcement system. Immigration judges:
- Determine removability and issue removal orders;
- Rule on detention and bond, directly affecting whether a person is held or released;
- Shape enforcement outcomes by interpreting and applying immigration statutes and regulations in individual cases.
These are not academic exercises. They are decisions that determine who may remain in the United States, who is detained, and who is deported—often to places where life or freedom may be at risk. In practical and legal terms, immigration adjudication is part of the execution of federal law in a law‑enforcement context. To treat it as something wholly separate from “law enforcement” for PCA purposes is to ignore how the system actually works.
Because immigration judges operate inside DOJ and their decisions are integral to the enforcement pipeline, assigning active‑duty military officers to that role is not a neutral “civilian” assignment. It is the use of armed forces personnel in the machinery of domestic law enforcement.
The DOJ’s position: a narrow, formalistic reading
The Office of Legal Counsel (OLC) has issued an opinion concluding that detailing military lawyers to serve as temporary immigration judges does not violate the PCA. Its reasoning, in essence, is that:
- The JAG officers are assigned full‑time to DOJ in a “civilian capacity”;
- They are supervised by civilian officials and follow DOJ policies;
- They are not deployed as “troops” in the field, but as adjudicators in an administrative system;
- Therefore, they are not being used “to execute the laws” in the sense the PCA forbids.
On this view, the key is the label and chain of command: if the military officer is temporarily slotted into a civilian role, under civilian supervision, the PCA is not triggered. The opinion also leans on the fact that immigration proceedings are formally “civil” rather than “criminal,” suggesting that this further distances the role from classic law‑enforcement activity.
Why the DOJ’s reasoning fails
- Function, not labels, defines “execution of the laws”
The PCA’s text and history focus on what the military does, not what agencies call the role. An active‑duty JAG officer ordered to serve as an immigration judge is still a member of the armed forces, subject to the Uniform Code of Military Justice, and performing a function that directly determines enforcement outcomes. The fact that DOJ describes the role as “civilian” does not change the functional reality: these officers are being used to execute federal immigration law over civilians.
Courts and commentators analyzing PCA questions have consistently emphasized function over form. If military personnel are placed in positions where they exercise governmental authority over civilians in the enforcement of domestic law, the PCA’s core concern is implicated—regardless of whether they wear a uniform or sit behind a bench.
- Immigration courts are embedded in a law‑enforcement system
The DOJ opinion treats immigration adjudication as if it were detached from enforcement, but immigration courts are structurally and operationally part of the enforcement apparatus. Removal orders, detention decisions, and credibility findings all feed directly into the government’s ability to enforce immigration law. That is precisely why the executive branch is turning to military lawyers: to relieve a law‑enforcement backlog and accelerate enforcement outcomes.
Using the military to solve a civilian law‑enforcement staffing problem is exactly the kind of substitution the PCA was meant to prevent. The statute is not limited to soldiers patrolling streets; it reaches any use of the armed forces “to execute the laws,” which plainly includes adjudicative functions that determine whether and how those laws are enforced against individuals.
- The “civil” label does not remove the law‑enforcement character
Immigration proceedings are formally civil, but their consequences—detention, deportation, family separation—are as coercive and life‑altering as many criminal sanctions. The PCA does not distinguish between “civil” and “criminal” enforcement; it speaks broadly of using the military to execute the laws. To suggest that the civil label insulates immigration adjudication from PCA scrutiny is to elevate form over substance in a way that undermines the statute’s protective purpose.
- The arrangement is unprecedented and destabilizing
Legal scholars and civil‑military experts have described the move to appoint large numbers of JAGs as immigration judges as “unprecedented” and deeply troubling. Historically, the United States has avoided embedding active‑duty officers in civilian adjudicative roles that directly affect domestic law enforcement. Breaking that norm risks normalizing military participation in civilian governance and blurring the line the PCA was designed to keep sharp.
Once the precedent is set that active‑duty officers can be used to fill civilian judicial or quasi‑judicial roles in law‑enforcement systems, it becomes easier to justify similar deployments in other contexts—administrative tribunals, regulatory enforcement hearings, or even specialized courts. That is not a slippery slope argument in the abstract; it is a realistic assessment of how executive power tends to expand once a legal barrier has been weakened.
Civil‑military relations and democratic legitimacy
Beyond statutory interpretation, there is a deeper concern: democratic legitimacy. The image of “soldiers in robes” deciding the fate of noncitizens in US immigration courts sends a powerful signal about who wields authority over civilians. Even if every individual JAG officer acts with integrity and professionalism, the structural message is that the military can be drawn into domestic adjudication when civilian systems are strained.
That is precisely the kind of normalization the PCA was meant to resist. The statute is not only about preventing overt military crackdowns; it is about preserving a culture in which civilian institutions, staffed by civilians, are responsible for enforcing and adjudicating domestic law. When the government turns to the armed forces to fill those roles, it chips away at that culture and invites future administrations to push the boundary further.
Conclusion
Assigning active‑duty judge advocates to serve as immigration judges within the Department of Justice is not a harmless administrative fix. It is the use of armed forces personnel in a core law‑enforcement function: adjudicating who is detained, who is removed, and how immigration laws are applied to individuals.
The DOJ’s contrary view depends on narrow labels and formalistic distinctions that do not withstand functional scrutiny. Immigration adjudication is part of the execution of federal law, and using military officers in that role violates both the letter and the spirit of the Posse Comitatus Act.
David M. Crane is a global leader in international criminal justice and the founding Chief Prosecutor of the UN Special Court for Sierra Leone. He has spent decades shaping accountability mechanisms around the world, including serving as a driving architect behind the Special Tribunal for the Crime of Aggression against Ukraine. Crane is a distinguished scholar of international law, a former senior US national security official, and a leading voice on the rule of law, state responsibility, and the legal limits on the use of force.
