Criminal Justice & the Rule of Law

Can Trump Use the Insurrection Act to Deploy Troops to American Streets?

Scott R. Anderson, Michel Paradis
Wednesday, June 3, 2020, 8:47 AM

If President Trump wants to follow through on his threats to deploy the military around the country, he may have to push one of America’s oldest emergency laws to its limits.

Military police in riot gear stand outside the White House on June 1, 2020. (Credit: Matt Kahn)

Published by The Lawfare Institute
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For the first time in decades, the U.S. military is patrolling the streets of the nation’s capital. And according to President Trump, the same may soon be true in other American cities as well.

On Monday, June 1, President Trump addressed the nation for the first time on the murder of George Floyd, the African American man whose death at the hands of a white police officer has motivated a wave of mostly peaceful nationwide protests, as well as some incidents of looting, vandalism and violence. Speaking from the White House, Trump expressed sympathy for Floyd and those angry over his death but nonetheless announced a hard line policy toward the broader civil unrest:

Today, I have strongly recommended to every governor to deploy the National Guard in sufficient numbers that we dominate the streets. Mayors and governors must establish an overwhelming law enforcement presence until the violence has been quelled.

If a city or a state refuses to take the actions that are necessary to defend the life and property of their residents, then I will deploy the United States military and quickly solve the problem for them.

Meanwhile, within Washington, D.C., Trump announced a more immediate response: “the deployment of thousands and thousands of heavily armed soldiers, military personnel, and law enforcement officers to stop the rioting, looting, vandalism, assaults, and the wanton destruction of property[,]” which was already underway by the time of his remarks.

At present, it’s unclear what exact military deployments Trump has directed. Nearly all of D.C.’s small National Guard contingent was already deployed to assist local police prior to Trump’s remarks. Some state National Guard units have been similarly mobilized by their respective governors, while others have reportedly been called into federal service, although it’s not clear where they are being deployed or what activities they will be pursuing. At present, however, the only actual deployment of active-duty service members confirmed by the Pentagon appears to be a contingent of around 250 members from military police and engineering units being stationed in the national capital area.

Trump’s decision to deploy these service members—and his threat to deploy more of them—raises a complicated set of legal questions. For more than a century, statutory restrictions on posse comitatus—a Latin phrase referring to the use of private parties to enforce the law—have limited the extent to which the military may be used for the sorts of law enforcement purposes Trump has identified. Congress, however, has installed a number of exceptions to posse comitatus that allow the military to provide various types of indirect support to law enforcement. It has also chosen not to extend these restrictions to members of the National Guard when acting under state authority, allowing them to engage in various law enforcement activities.

Together, these decisions provide a plausible legal basis for the limited set of military activities that the Trump administration appears to be pursuing thus far. But if he wanted to make good on his threat to use the military to enforce the law and suppress civil unrest elsewhere in the country, Trump would almost certainly have to invoke the much broader exception to posse comitatus restrictions provided by the Insurrection Act—a controversial move that has historically been reserved for extreme exigencies. Even then, there may be reasons to doubt whether Trump has the legal authority to act, as the current state of civil unrest in the United States is a poor fit for what the Insurrection Act is designed to address.

Posse Comitatus Restrictions

For more than a century, federal law has limited when and how the military may be used for law enforcement purposes. Originally enacted as part of the Posse Comitatus Act of 1878, these provisions are now codified as amended at 18 U.S.C. § 1385, which reads:

Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both.

Though framed as a criminal offense, no one has ever been prosecuted under this provision. Instead, it serves primarily as a statutory restriction on how various state and federal government officials may use the armed forces. Notably, while the statute applies directly only to the Army and Air Force, Defense Department policy extends the same limitations to the Navy and Marine Corps (though not the Coast Guard or newly established Space Force) “with such exceptions as the Secretary of Defense may authorize in advance on a case-by-case basis.”

Both the courts and the executive branch have interpreted this posse comitatus restriction as applying where the military is used for the purposes of civilian law enforcement. It does not apply to activities pursued by the military for other valid purposes, even where those activities may resemble or incidentally benefit civilian law enforcement activities. For example, military personnel may enforce laws, investigate crimes, and even arrest people who are in the military or on military bases without violating the posse comitatus restriction, because these activities are understood to be for military purposes.

There are also constitutional exceptions to posse comitatus restrictions rooted in the president’s own constitutional authority. Defense Department guidelines describe “homeland defense” as a “constitutional exception” to the posse comitatus restriction, meaning that measures necessary to guarantee national security from external threats are not subject to the same limitations.

Trump’s remarks, however, suggest that he is not attempting to invoke these exceptions. To the contrary, his emphasis on his “oath to uphold the laws of the nation” and the need to preserve “rule of law” strongly suggest that his objective in deploying the military is strictly law enforcement. This in turn means that posse comitatus restrictions should apply.

Federal courts, meanwhile, have struggled to reach consensus on what exactly the posse comitatus restriction prohibits. Some have treated the restriction as a near complete bar on any form of military involvement in law enforcement activities. Others have held that it only prohibits military participation in activities that involve a risk of direct conflict with civilians. For its part, the executive branch interprets this case law as applying the posse comitatus restriction where civilian law enforcement authorities make “direct active use” of military personnel to execute the laws, where the use of military personnel “pervades the activities” of civilian law enforcement, or where military authorities “subjec[t] civilians to military regulations, proscriptions, or compulsions”—but not necessarily as prohibiting other forms of military involvement in law enforcement activities.

Since the 1980s, Congress has tried to clarify the scope of posse comitatus restrictions by enacting express statutory exceptions for certain types of military support for civilian law enforcement. The most substantial set of these authorities allows the military to assist civilian law enforcement agencies with a wide array of equipment, information, services and training. But Congress has also required that such efforts “not include or permit direct participation by a member of the [armed services] in a search, seizure, arrest, or other similar activity” unless otherwise authorized by law,” effectively reimposing the narrower view of posse comitatus restrictions. A handful of other statutory provisions provide similar exceptions to posse comitatus restrictions for certain other limited purposes, including enforcing neutrality laws, protecting select national parks and even implementing quarantines. But none seems relevant to the present circumstances of nationwide protest.

These existing exceptions for support for law enforcement may provide a legal basis for some of the more limited activities that the Trump administration appears to be considering. Under these authorities, for example, the active-duty engineering and military police personnel currently staged near Washington, D.C., could be deployed to advise local police, operate and maintain temporary headquarters and other facilities, or even provide transportation and intelligence services. But these personnel could not participate in arrests, seizures, or other action risking confrontation with civilians without running afoul of posse comitatus restrictions. If Trump actually wishes to pursue such activities, he will need to rely on a different set of legal authorities.

The National Guard

The rules governing posse comitatus as applied to National Guard forces, meanwhile, are different from those that apply to active-duty military personnel. Each state within the United States maintains its own National Guard as a vestige of the state militias that played a prominent role in the original constitutional vision of U.S. national defense. Whether posse comitatus restrictions apply to members of these National Guards depends under whose authority they are acting and in what capacity.

Traditionally, the state militias were answerable solely to their respective governors unless called forth by Congress and placed under the president’s authority as commander in chief, pursuant to the Constitution’s Militia Clauses. But in 1933, President Franklin Roosevelt successfully pushed for the so-called National Guard Bill—effectively making every member of each state’s National Guard a member of the Army Reserve as well and creating the separate Army National Guard of the United States. The Air Force followed suit several years later when it split from the Army, resulting in the similar Air National Guard.

In effect, members of each state’s National Guard wear two hats: state and federal. This is often referred to as the divide between the National Guard’s “Title 32 status”—a reference to the portion of the U.S. Code that governs National Guard units—and its “Title 10 status”—the portion that governs the regular armed forces and Defense Department. In the ordinary course, members of the National Guard act only in their Title 32 capacity, meaning they are under the command of the governor of their state. But Congress has used its authority under the Militia Clauses to allow the National Guard to be called into federal service in a number of circumstances. When this occurs, federalized members of the National Guard begin acting in their Title 10 capacity under the command of the president in the same manner as reserve members of the regular armed forces.

The capacity in which members of the National Guard act largely governs the extent to which they are subject to posse comitatus restrictions. In the absence of an express activation of their Title 10 status, members of the National Guard remain the armed forces of their individual states under Title 32. As a result, they are not subject to posse comitatus restrictions. Once called into federal service, however, members of the Guard cease acting as agents of the state and instead become armed forces of the federal government to whom posse comitatus restrictions apply.

One notable exception to this straightforward system is the National Guard of Washington, D.C. While D.C. is not a state, Congress authorized Washington to form its own militia in the early 1800s. This entity later became the D.C. National Guard. Subsequent laws governing the D.C. National Guard were either enacted by Congress or adopted by city officials pursuant to delegations from Congress, making them a type of federal law. Notably, for this reason, the president—and not the city’s mayor—is the commander in chief of the D.C. National Guard, though the president has since delegated this authority to the secretary of the army.

As a federal military force, one might think that the D.C. National Guard would be subject to posse comitatus restrictions. But both law and practice run in the opposite direction. The Justice Department has generally asserted that the D.C. National Guard, like its state counterparts, can act in a nonfederal “militia” capacity that is not subject to posse comitatus limitations—relying less on a federal-state distinction and more on a distinction between Title 10 and Title 32 authorities. Some federal statutes appear to make a similar assumption in treating the D.C. National Guard as the effective equivalent of a state National Guard. And the Justice Department has also argued that provisions of the D.C. Code authorize the use of the D.C. National Guard for law enforcement purposes, providing statutory exceptions to posse comitatus restrictions even if they were to apply. Consistent with this view, the D.C. National Guard has been used regularly to supplement the D.C. police force in certain capacities, such as by providing added security at presidential inaugurations and similar major events.

These authorities account for the majority of U.S. soldiers who are currently participating in efforts to suppress civil unrest around the country. Most are members of state National Guards who have been mobilized by their respective governors. In Washington, D.C., they are members of the city National Guard who are acting under the direction of the president. Neither of these groups is subject to posse comitatus restrictions, so long as they continue to operate in their Title 32 capacities. That said, if Trump wishes to take control of state National Guard units or direct the D.C. National Guard to pursue activities unrelated to the city, as he has suggested, then he will need to bring them under his Title 10 authorities. This will in turn make these members of the National Guard subject to the same posse comitatus restrictions as active-duty members of the military, barring the availability of some other exception.

The Insurrection Act

If the president truly wants to deploy U.S. soldiers to “dominate the streets” in cities around the country as he threatened in his June 1 remarks, he will need to go beyond the authorities discussed above and invoke perhaps the most significant exception to posse comitatus restrictions on the books: the Insurrection Act. To date, however, Trump hasn’t invoked this authority—and there may be good legal and political reasons why he’s hesitated to do so.

Originally enacted in 1807 and modeled on similar statutes dating back to the beginning of the republic, the Insurrection Act—which is now codified as amended at 10 U.S.C. Ch. 13—operationalizes the authority “[t]o provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions” provided to Congress by the Constitution’s Militia Clauses. Specifically, it authorizes the president to deploy both active-duty military and federalized National Guard members to address situations of civil unrest in the country, provided that certain conditions are met.

The president cannot invoke the Insurrection Act secretly or ambiguously. Before doing so, he is required to make a public proclamation directing “the insurgents to disperse and retire peaceably to their abodes within a limited time,” thereby providing anyone involved in the civil unrest an opportunity to retreat. Perhaps more importantly, this requirement ensures that the president publicly acknowledges and discloses his decision to invoke the Insurrection Act, allowing Congress and the public to respond accordingly.

Substantively, the Insurrection Act authorizes the president to deploy the military domestically in four sets of circumstances:

  • Where the president receives a request for assistance from the legislature of a state that is experiencing “an insurrection ... against its government[,]” or that state’s governor if its legislature cannot be convened, under 10 U.S.C. § 251.
  • Where the president “considers that unlawful obstructions, combinations, or assemblages, or rebellion against the authority of the United States, make it impracticable to enforce the laws of the United States in any State by the ordinary course of judicial proceedings,” under 10 U.S.C. § 252.
  • Where “any insurrection, domestic violence, unlawful combination, or conspiracy” either “so hinders the execution of the laws of [a] State, and of the United States within th[at] State, that any part or class of its people is deprived of a right, privilege, immunity, or protection named in the Constitution and secured by Law, and the constituted authorities of that State are unable, fail, or refuse to protect that right, privilege, or immunity, or to give that protection,” under 10 U.S.C. § 253(1)—in which cases, the statute notes, that state “shall be considered to have denied the equal protection of the laws secured by the Constitution.”
  • Where “any insurrection, domestic violence, unlawful combination, or conspiracy ... opposes or obstructs the execution of the laws of the United States or impedes the course of justice under those laws,” under 10 U.S.C. § 253(2).

Most invocations of the Insurrection Act have taken place pursuant to § 251 at the request of state officials, including the most recent—namely, President George H.W. Bush’s 1992 deployment of federal troops to suppress the Los Angeles riots. (That said, it’s not entirely clear which provision of the Insurrection Act Bush was relying on, as only California’s governor, not its legislature, requested the intervention and Bush’s proclamation and related executive order do not specify.) Section 252, meanwhile, has been applied primarily to situations of armed uprising, rampant violent criminality and widespread rioting. By contrast, § 253 has most commonly been used in the context of civil rights to authorize the use of federal troops to enforce school desegregation and defend civil rights activists.

Together, these provisions delegate an immense amount of authority to the president. This is amplified by the fact that several of these provisions—especially § 252—hinge on the president’s subjective evaluation of the prevailing circumstances. What’s more, every one of these provisions employs broad and undefined terms like “unlawful obstructions” and “domestic violence” that allow the president significant leeway in interpreting when and how they should be applied.

This does not, however, mean that these provisions are blank checks. Even absent a request for assistance from a state government, the Insurrection Act seems to expect that the president will invoke its authority only where certain conditions are met. And it’s not at all clear that the current circumstances meet these standards.

For § 252 to be available, for example, the president is supposed to conclude that civil unrest has made it “impracticable” for the courts and broader justice system to operate normally. Yet there are few signs that the justice system has ceased to be effective, even in areas that have experienced looting and violence. In D.C., the closest one can get is a decision by the U.S. Court of Appeals for the Federal Circuit to close early on June 1 and 2 due to its proximity to the White House and related protests. Similarly, § 253(1) is intended for use in responding to violations of the Equal Protection Clause. But it’s unclear what protected class of persons’ civil rights may have been duly threatened by the recent unrest so as to reach this threshold.

As for § 253(2), Trump’s remarks did not hint at what federal authority those engaged in civil unrest might be obstructing, but he repeatedly referenced the need to protect individuals’ “life and property.” Both, however, are entitlements that the states are primarily responsible for protecting, not the federal government. Indeed, most of the activities that Trump likely sees as threatening life and property aren’t violations of federal law at all. Moreover, § 253(2)’s requirement that civil unrest “oppos[e] or obstruc[t]” federal authority has special import when one considers that § 253 was enacted as part of post-Civil War legislation aimed at ensuring that southern states respect the rights given to black Americans by federal law. In this context, it clearly seems to anticipate a more deliberate effort at thwarting federal legal rights than simple unlawfulness. But it’s not clear what those currently engaged in civil unrest have done to rise to this threshold. All told, invoking § 253(2) could open the door to using the Insurrection Act to enforce laws on all sorts of conduct usually left to state regulation—an outcome that appears quite in tension with the federalism concerns clearly motivating many of the safeguards contained within the Insurrection Act.

In spite of these potential concerns, however, it’s unclear whether federal courts will be willing to meaningfully interfere if Trump were to invoke the Insurrection Act. Direct legal challenges may not reach resolution before the president’s use of the military is completed. And the invocation of the Insurrection Act raises separation of powers questions that courts may be hesitant to confront. Of course, these questions would arise outside the usual context of foreign affairs and national security in which the executive often receives extensive deference, and in a domestic arena wherein Congress’s own constitutional role is even more readily established. But given the Insurrection Act’s own broad language and the sometimes questionable ways in which prior presidents have used the authority without congressional response, courts may not see a clear enough conflict between Congress and the executive to warrant intervention.

Recklessly invoking the Insurrection Act, however, could bring more litigation risk after the fact. Criminal defendants have at times sought to suppress evidence by challenging the legality of military involvement in their arrests, a remedy that some courts have recently suggested might be appropriate in the event of “widespread and repeated violations” of posse comitatus with no sign of correction by the federal government. In others, they have successfully used posse comitatus violations to fight back against criminal charges that hinge in part on the lawfulness of government conduct. And there has been some suggestion that posse comitatus violations could place certain searches and seizures in violation of the Fourth Amendment.

All of these legal claims promise some future judicial scrutiny of the president’s decisions. And in some cases they may even make criminal prosecution of those involved in the current civil unrest more difficult—an ironic outcome, given President Trump’s own stated desire to see them “prosecuted to the fullest extent of the law.”

Meanwhile, those looking to stop Trump from deploying more federal troops to U.S. cities will likely need to look beyond the federal courts for a remedy. The primary check on use of the Insurrection Act has been political, given the unpopularity of its use—a factor that may prove particularly persuasive given that Trump is a vulnerable candidate in an election year. Members of Congress, meanwhile, can use their oversight authorities to shed light on the deficiencies in the legal and policy grounds for Trump’s threat to invoke the Insurrection Act. Congress could seek to expand the posse comitatus restrictions or limit the Insurrection Act through legislation, forcing Trump to either abandon his plans or find an alternative legal basis for them. While freestanding efforts may have trouble overcoming a likely presidential veto, there will be opportunities to insert such provisions into upcoming omnibus legislation such as the 2021 National Defense Authorization Act—a step that some on Capitol Hill are already discussing.

Doing so will require support from congressional Republicans, especially in the Senate. Yet there have been enough negative reactions within the president’s own party that this remains a possibility. That fact alone may deter Trump from pushing the outer limits of his own authorities. And if it does not, then Congress will have to reconsider whether it wants to delegate such broad authorities to the president in the future, even if it cannot stop this president from abusing them today.


There is a perverse irony to today’s debate over the Insurrection act. The restrictions on posse comitatus that currently protect protesters from federal overreach were originally installed after the Civil War as part of an effort to limit the federal government’s authority to protect the civil rights of black Americans in the South. During the Reconstruction period, President Ulysses Grant deployed the military to defend freedpeople in the former Confederacy. In 1878, Congress passed the Posse Comitatus Act to help roll back those federal protections, permitting a new wave of racist violence and oppression.

Meanwhile, the part of the Insurrection Act that the president is now using to threaten those protesting George Floyd’s murder was first codified, not in 1807, but as part of the Civil Rights Act of 1871—a law empowering the federal government to guarantee equal rights before the law. Perhaps its most significant use until now was in 1965, when President Lyndon Johnson deployed the military to protect civil rights protestors from police violence on the march from Selma to Montgomery, Alabama. That the same law may now be used to expose protestors objecting to police violence to the might of the U.S. military is nothing short of tragic. Yet it is also a sign of the need, perhaps, to adjust the country’s most important legal authorities to better reflect our historical moment.

Scott R. Anderson is a fellow in Governance Studies at the Brookings Institution and a Senior Fellow in the National Security Law Program at Columbia Law School. He previously served as an Attorney-Adviser in the Office of the Legal Adviser at the U.S. Department of State and as the legal advisor for the U.S. Embassy in Baghdad, Iraq.
Michel Paradis is a senior attorney in the U.S. Dept. of Defense, Military Commissions Defense Organization. He is also a lecturer at Columbia Law School and a fellow at the Center on National Security. The views expressed are his own and do not reflect the position of the U.S. government or any agency or instrumentality thereof.

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