For nearly 150 years, the Posse Comitatus Act has limited the power of U.S. presidents to use the military domestically. This 1878 law bars the federal armed forces from engaging in civilian law enforcement except when expressly authorized by Congress. It embodies an American tradition of rejecting military interference in civilian affairs, premised on the idea that allowing presidents free rein to turn federal troops inward against the people would endanger democracy, free expression, and even public safety.
Yet roughly one-fifth of American military personnel are not generally subject to the Posse Comitatus Act. These service members are not part of the active-duty armed forces; rather, they are part of their state’s or territory’s National Guard. They receive the same training, carry the same weapons, and wear the same uniforms as members of the U.S. Army or Air Force. However, unless they have been called into federal service, they are governed by state and territorial laws that vary significantly from jurisdiction to jurisdiction.
The Brennan Center has compiled and annotated these laws and now presents them through an interactive map. Our compendium reveals that, in many states and territories, the laws that normally apply to National Guard forces impose relatively few constraints on the governor’s authority as commander in chief — a dangerous state of affairs that legislatures can, and should, rectify.
Background
The National Guard is the modern incarnation of the colonial and state militias. Its members are part-time soldiers who lead regular civilian lives when they are not on duty. When mobilized by their governor, National Guard personnel may serve in any number of capacities. Providing disaster relief and responding to civil unrest are among their most important traditional functions.
Members of the National Guard may also be called into federal service, or “federalized,” by the president. When that happens, they effectively become members of the active-duty armed forces until they are returned to state status. Federalized National Guard forces are under the president’s command and may be used for federal missions, up to and including deployment to fight overseas. In this status, they are subject to federal law, including the Posse Comitatus Act.
There are 54 National Guards — one for each state and for the District of Columbia, Guam, Puerto Rico, and the U.S. Virgin Islands. Almost everything about these forces — their size, organization, training, uniforms, and equipment — is regulated by the federal government, which also provides the vast majority of each National Guard’s funding.
Nonetheless, historically, the National Guard’s training, mission, and culture were distinct from those of the active-duty armed forces. The latter are full-time, professional soldiers, ready at a moment’s notice to deploy to combat foreign enemies. Guard members have traditionally been seen as “citizen soldiers” who hold civilian jobs during the week and train on weekends. In contrast to a professional army, the Guard was a strategic reserve that could be called up to fight if the United States were invaded or became involved in a conflict requiring an extraordinary mobilization. More often, however, they were activated to serve their local communities in times of urgent need. Accordingly, deployments of National Guard forces by their governors did not raise the same concerns that have historically surrounded presidential deployments of the active-duty military inside the United States.
In recent decades, however, the distinction between active-duty and National Guard forces has blurred. Since the end of the draft following the conclusion of the Vietnam War, and especially since the late 1990s, the Department of Defense has transformed the National Guard from a reserve force into an operational component as part of the Pentagon’s Total Force Policy. National Guard units are now trained and equipped to the same standard as their active-duty counterparts. And because of the United States’ unprecedented reliance on the Guard and Reserves during the wars in Afghanistan and Iraq, a large proportion of Guard personnel have significant combat experience. In 2010, the general in charge of the National Guard’s domestic operations said that a decade at war had transformed the Guard from a “strategic reserve” into “a battle-tested, hardened organization . . . with many combat veterans.” Today’s National Guard is therefore increasingly difficult to distinguish from a professional army.
Moreover, President Donald Trump has used a 2006 law to permit federal use of state National Guard forces in unprecedented ways. Under Section 502(f)(2)(A) of Title 32, the president or secretary of defense may ask governors to deploy their National Guard forces to perform federal missions or operations at the federal government’s expense. Although this law was intended to facilitate federal payment for deployments related to natural disasters or certain statutorily authorized homeland security missions, Trump has relied on it to request that states led by friendly Republican governors deploy National Guard forces to control crime in Washington, DC, Memphis, and New Orleans, over the objections of local officials. Guard forces in those cities are taking significant direction from the federal government, and at least in Washington, DC — where out-of-district Guard forces are coordinating with the DC National Guard, which is always under the president’s command and control — they are reporting through a federal chain of command. Nonetheless, because they have not been formally federalized, the administration does not consider them to be subject to the Posse Comitatus Act. Any limitations on their activities must come, instead, from state or District of Columbia law.
In the wake of these developments, states’ rules for their National Guards have taken on new importance. Apart from restrictions that apply to all state officials, such as those contained in federal civil rights laws, there is no federal law limiting what a state can do with its National Guard. Instead, these jurisdictions decide for themselves what is permitted. In other words, there is not one body of laws governing domestic deployment of the military in the United States — there are 55.
Our Compendium of State Laws
This compendium gathers the constitutional provisions and statutes governing the use of the National Guard (or “militia,” depending on how a state’s laws are written) in all 50 states plus the District of Columbia, Guam, Puerto Rico, and the U.S. Virgin Islands. These laws apply when National Guard forces are deployed under state command and control, even if the deployment occurs at the president’s request under Section 502(f). An interactive map, below, summarizes each jurisdiction’s laws, highlighting key legal issues. A downloadable spreadsheet lists the relevant statutory and constitutional text for each jurisdiction.
Not every provision related to the National Guard or militia is included. We have not, for example, included laws related to pay, veterans’ benefits, or military justice. Instead, we have aimed to capture the laws that control how each state and territory can use its National Guard within its own borders while under state control.
We have focused on a few important questions: First, does the law enumerate the specific circumstances in which the governor may activate the National Guard, or instead give the governor discretion to decide when doing so is appropriate? In most jurisdictions, the law sits somewhere between these two poles. For example, a number of state legislatures have defined a list of permissible purposes for deployment, but the list is so long and inclusive that it operates more as permission than as a constraint.
Second, how do states and territories handle the National Guard’s participation in law enforcement? Does state law grant the Guard expansive law enforcement powers whenever it is deployed, or only under certain circumstances? Are there any affirmative restrictions on the Guard’s ability to participate in law enforcement? A subsidiary question is whether state or territorial law considers members of the National Guard to be “peace officers” — a legal term for anyone authorized to enforce the law, make arrests, and maintain public order. In states that make their National Guard personnel peace officers by default, such as Nebraska and Arkansas, members of the Guard have the same powers as professional civilian law enforcement officers, even though most National Guard personnel have little or no law enforcement training.
Third, does state or territorial law allow the governor to declare martial law? The term “martial law” has no established legal definition, but it is generally understood to refer to a power that allows the military to push aside civilian authorities and exercise jurisdiction over the population of a particular area. In other words, it means temporary military rule in an emergency. Such a power is difficult to reconcile with the U.S. Constitution. The idea of the military supplanting civilian authorities for any reason, no matter how temporary, is simply incompatible with our constitutional system, under which the military is subject to civilian rule and the Bill of Rights limits the military’s coercive powers over the people. Yet, for a period of time from the mid-19th century until the Second World War, it was not unusual for states to declare martial law in an emergency. The U.S. Supreme Court even held in 1849 that states could do so as long as the declaration was authorized by state law. While no governor has declared martial law since 1963, many states still have laws on the books that permit the governor to do so.
Finally, while this compendium focuses on the National Guard, we have also included state laws that establish “state defense forces.” These are a kind of auxiliary militia that Congress permits the states to maintain. State defense forces cannot be federalized. They are not subject to federal regulation, nor can they receive federal funding. While all but two jurisdictions — the District of Columbia and the U.S. Virgin Islands — have laws allowing for the creation of a state defense force, only 22 states and Puerto Rico currently maintain them. Given the prohibitive cost of supporting a military force of any size, these forces tend to be small and are often made up of unpaid volunteers. Yet the lack of federal regulation of state defense forces is one of the reasons they warrant extra attention: They are the only category of military force that is not subject to the training requirements and recruitment standards that Congress imposes on the National Guard and the branches of the U.S. Armed Forces, nor does the Uniform Code of Military Justice apply to them.
Themes
When comparing the 54 jurisdictions included in this compendium, several themes emerge:
State and territorial law governing use of the National Guard is often vague or underdeveloped, particularly with respect to the Guard’s participation in law enforcement. In almost all jurisdictions, the law at least implies that the National Guard or militia may be used to “execute the law” in certain circumstances, but many states do not clearly articulate what that means. The scope of the Guard’s law enforcement powers, and how they differ, if at all, from the law enforcement powers of civilian police, frequently go unexplained. Moreover, despite the inherent dangers of using troops as domestic police, not a single state or territory has an analogue to the Posse Comitatus Act that would prohibit the use of National Guard forces for law enforcement without express statutory authority.
A few states have laws that violate protections guaranteed by the U.S. Constitution. For example, an Illinois statute, 20 Ill. Comp. Stat. Ann. 1805/84, purports to allow the National Guard, whenever it is deployed in response to civil unrest, to “arrest any person or persons in view without process” and to then detain them indefinitely. This sweeping authority is incompatible with procedural guarantees in the Fourth, Sixth, and Fourteenth Amendments and seems also to disregard the constitutional right to petition for the writ of habeas corpus. Similarly, Iowa Code § 29A.46 purports to allow the governor to set up military tribunals to prosecute civilians in areas that the governor has placed under martial law. This authority conflicts with both the Sixth and Fourteenth Amendments (not to mention the Iowa Constitution, which provides that the “military shall be subordinate to the civil power”). While the federal courts would have the authority to invalidate attempts to exercise these authorities to their full extent, judicial relief might come only after Americans’ constitutional rights have already been violated.
A surprising number of states have laws permitting the declaration of martial law that conflict with the state constitution. Many states that have a law authorizing the governor to declare martial law also have a provision in their constitution stating that the military is, or must always be, subordinate to the civil power. The existence of a power to declare martial law is incompatible with this kind of constitutional restriction. In Tennessee, the textual conflict is particularly stark: Article I, Section 25 of the state constitution expressly forbids the declaration of “martial law,” but a state statute, Tenn. Code Ann. § 58–1–112, allows the governor to declare “martial rule.” This term is synonymous with martial law, thus rendering the statute unconstitutional on its face. To be sure, such constitutional conflicts should cause state courts to invalidate any attempt to exercise powers of this sort. Yet there is still reason to be concerned. To start, the success of a legal challenge would be contingent on other, technical legal matters, including who has standing to sue. Moreover, the judicial system can move slowly even when the law is clear. Harms to the public caused by an unlawful declaration of martial law may be difficult for the courts to remedy after the fact.
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In short, our analysis of state laws and constitutional provisions regarding the National Guard reveals a sprawling legal landscape that is rife with internal contradictions and constitutional tensions. These laws often give governors strikingly broad powers to deploy military force within their states. Meanwhile, state legislatures have little role in overseeing and regulating the activities of their state’s or territory’s National Guard. The resulting status quo is ripe for abuse and in need of reform — such as the state-level versions of the Posse Comitatus Act we recommended in a 2024 report.
A law recently enacted in Virginia includes additional reforms that other state legislatures should consider. HB286 strengthens legislative oversight of the Virginia National Guard by requiring the state’s adjutant general (the highest-ranking military officer in a state’s National Guard) to submit a detailed annual report to the General Assembly. It also tempers the governor’s discretion to deploy troops outside of statutorily specified emergencies. Finally, the measure requires the creation of a working group to develop additional reforms related to the National Guard.
We hope that this compendium will provide a resource for legislators and policymakers who may be considering changes to their state’s laws; for advocates and litigators who focus on domestic deployments of the military, including National Guard deployments under state law or Title 32; for journalists who cover the legal issues surrounding domestic military deployments; and for members of the public who want to understand the laws that govern the use of National Guard forces in their own communities.
