Over the last few months, the Trump administration has used military and militarized force to quell Black Lives Matter protesters, citing domestic security concerns. Now, as Trump continues to threaten to send in active-duty troops to crack down on civil rights protests, he has also been explicit about the possibility of using law enforcement to interfere with the election. He threatened to command law enforcement to patrol the polls to prevent purported voter fraud; he told Fox News’ Judge Jeanine that he would use the Insurrection Act to “put down” election night unrest if he wins; and former advisor Roger Stone suggested that Trump should use active duty military, the FBI, and U.S. Marshals to interfere with the election and stop state officials from counting votes. As with much of what Trump says, it’s hard to know whether he intends to follow through. But the mere fact that he has made these threats has the potential to deter voters (which may be the point). And any attempt to put his words into action would raise serious legal questions. No matter how broad a president’s discretion on matters of national security, nothing empowers the president to exercise his authority to interfere with an election.
Statutory and Constitutional Limits on Deploying Military and Militarized Forces
In our democracy, the president has only the powers granted by the Constitution or lawfully delegated by Congress. The Constitution provides the president neither exclusive control over the military, nor emergency powers to command military forces. This is not a technical question of military law; this is about a broad balance of powers to ensure that no president has a personal “palace guard” at their command. The Founders intentionally divided control over the military between Congress and the president as a bulwark against tyranny they had experienced under a monarchy. The Declaration of Independence, for example, decried the tyrannical conduct of George III, including that “[h]e has kept among us, in times of peace, Standing Armies, without the Consent of our legislatures.” A fundamental feature of our Constitution is preventing unchecked presidential power to use the military for domestic law enforcement purposes.
Specifically, the Constitution reserves to Congress the power to legislate how the militia may be deployed domestically. The Militia Clauses in Article I, § 8 authorize Congress “[t]o provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions.” This legislative power is related to the obligation that the Constitution imposes on the United States as a whole to guarantee the states a “Republican Form of Government,” and to protect the states against invasion and, “on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic Violence.” The president’s lawful authority to deploy troops for domestic law enforcement is constitutionally limited, therefore, to the instances where Congress prescribes it. It would be the ultimate subversion of these constitutional provisions to allow the president to use any statutory authority to deploy militarized forces for law enforcement surrounding an election — the defining feature of our republican form of government.
As a general matter, Congress has prohibited the use of military force for domestic law enforcement purposes absent express constitutional or statutory authorization. In 1878, Congress passed the Posse Comitatus Act, which provides criminal penalties for anyone who “willfully uses any part of the Army or Air Force as a posse comitatus”—that is, as an auxiliary of law enforcement—“or otherwise to execute the laws, … except in cases and under circumstances expressly authorized by the Constitution or Act of Congress.” The Act has come to be understood as enshrining the bedrock democratic principle that use of the military to regulate civilians is antithetical to liberty.
More broadly—beyond the specifics of the Posse Comitatus Act and its exceptions—a whole set of federal laws make it illegal for the military or federal law enforcement to interfere with an election in any way. Deploying armed federal agents—whether military or civilian—to polling places is itself illegal. Several federal laws explicitly prohibit (and, in fact, criminalize) armed federal agents at polls: 18 U.S.C. § 592 prohibits armed federal agents (military or civilian) from being at polling places at all; 18 U.S.C. § 593 prohibits members of the military from interfering in an election, including by intimidating voters or interfering with election officials; and 18 U.S.C. § 595 prohibits federal employees from using their official authority to interfere with the election. (Several statutes with civil penalties prohibit voter intimidation as well, discussed in more depth below).
In the last several months, Trump has sought to invoke a number of statutory authorities to call forth branches of the military, various states’ National Guards, and civilian armed federal agents to suppress protests against police violence, campaign as a “law and order” president, and “take over” politically disfavored cities. As we explain below, however, there are statutory and constitutional limits on Trump’s ability to deploy the military and militarized law enforcement against American civilians, and, specifically, limits on his ability to do so in a manner that interferes with the election or intimidates voters.
The Insurrection Act
The Insurrection Act, an exception to the Posse Comitatus Act, permits the domestic deployment of the military under circumscribed terms. The Act is traditionally understood as affording the president broad authority, subject only to prudential restraint. For example, Defense Secretary Mark Esper testified before Congress that the president has total discretion under the Act, even while acknowledging that the insurrection power “should only be used as a matter of last resort and only in the most urgent and dire of situations.” This understanding likely stems from a landmark Supreme Court decision, Martin v. Mott, which recognized broad presidential discretion under an Insurrection Act precursor during the War of 1812 when President James Madison thought British troops were going to invade our new nation. It held that “the authority to decide whether the exigency has arisen, belongs exclusively to the President, and that his decision is conclusive upon all other persons.”
Even if broad, the president’s authority under the Insurrection Act is not limitless or immune to judicial review. The constitutional separation of powers provides a meaningful constraint that courts can and should enforce, especially if the Act is abused for political gain. The Constitution provides Congress, not the president, the power to provide for when the military may be deployed domestically. If the president may exercise this statutory authority on a whim, completely unchecked by the courts, then the president is free to usurp Congress’s legislative authority to “provide for” the domestic use of the military. That is an unconstitutional result. To uphold the separation of powers, the president’s exercise of power under the Insurrection Act must be limited to the meaning of its statutory terms and subject to judicial review.
Judicial review is all the more imperative in a scenario where the president abuses the Insurrection Act to deploy troops in an attempt to tilt the election. When the early Supreme Court recognized the president as the sole arbiter of whether a domestic emergency justifies military response, it presumed that certain checks on presidential power were built in. First, it presumed the president was appropriately vested with the “high and delicate” power of determining when military force is necessary because it presumed the president respected the constitutional duty to “take care that the laws be faithfully executed.” Second, the Court presumed that the president possessed “the high qualities . . . of public virtue, and honest devotion to the public interests.” And third, it presumed that “elections, and the watchfulness of the representatives of the nation” would serve as “checks . . . to guard against usurpation or wanton tyranny.” None of those presumptions hold true if Trump, for example, uses military force to undermine the very election that is meant to serve as a “check” against such “wanton tyranny.” Neither vague proclamations of civil unrest by “anarchists,” nor assertions of “voter fraud” are a justification to circumvent the law.
Cities and states, therefore, can seek judicial review of an Insurrection Act invocation or threatened invocation that disrupts the election. There are several arguments they can marshal. First, the president’s invocation of the Act exceeds his statutory authority and therefore violates the Insurrection Act itself and the constitutional separation of powers. This argument is strongest where the proclamation of a so-called “insurrection” or “domestic violence” diverges from reality, as when Trump admitted while announcing his February 2019 national emergency proclamation that he “didn’t need to do this.” (Our organization, Protect Democracy, challenged this proclamation in court.) If the Insurrection Act is construed so broadly as to allow the use of military force to quell largely peaceful protests around the election, the Act, which operates as an exception to the Posse Comitatus Act, would swallow the rule, frustrating Congress’s constitutional prerogative to control when the president can deploy military force to American streets.
Second, cities and states can challenge the president’s invocation of the Act as in bad faith. Even while holding that the president can exclusively determine whether to call forth the militia, the Supreme Court in Martin v. Mott recognized that the president, like every public officer, is only “presumed to act in obedience to his duty [to ensure faithful execution of the laws], until the contrary is shown.” This qualification indicates that the presumption of good faith, on which deference to the president’s determination is founded, may be rebutted, subjecting the president’s determination to judicial review. A bad faith claim would have a long factual record to draw upon of this president abusing his power for his own political and personal gain.
Third, apart from any statutory violation of the Insurrection Act itself, use of the Act to deploy the military in connection with the election would violate various constitutional principles and rights, including potentially the First Amendment, equal protection, due process, and the Faithful Execution Clause.
The National Guard & 32 U.S.C. § 502(f)
The National Guard, composed of 54 separate state and territorial organizations, are by default state entities and subject to state laws and state command almost all of the time. It is rare for the National Guard to be “federalized” and brought under the president’s command and control. This is by constitutional design: Article I explicitly reserves to the states “the Authority of training the Militia.”
When federalized, National Guard units essentially become part of the federal military. This means, as discussed above, that the Posse Comitatus Act prohibits their use for domestic law enforcement—unless the president can invoke the Insurrection Act (or another statutory exception). But when the president or Secretary of Defense calls National Guard members to serve missions in what’s known as a “hybrid” status, they are not subject to the Posse Comitatus Act. This is because while in hybrid status, National Guard troops serve federal missions while remaining under their state governors’ command and control—they are neither “federalized,” nor fully under the typical state control.
Congress has limited permissible hybrid status activities in Title 32 of the U.S. Code. Under 32 U.S.C. § 502(f), National Guard units may “be ordered to perform training or other duty,” which includes “[s]upport of the operations or missions undertaken by the member’s unit at the request of the President or Secretary of Defense” (and with the consent and at the command of their states’ governors). Under Attorney General William Barr’s interpretation, this provision—a subpart of a provision on National Guard training exercises—would give the Trump administration expansive authority to order out-of-state National Guard units to serve any missions the president requests.
But Congress cannot have intended § 502(f) to serve as a catchall provision authorizing all federal missions under the guise of “training exercises” and carve out such a broad exception to the posse comitatus rule. Nothing in the legislative history points to any such intent to create such a sea change in how the National Guard operates. Congress “does not, one might say, hide elephants in mouseholes.”
Nor should the Trump administration be permitted to circumvent the posse comitatus rule by ignoring the critical requirement that National Guard troops remain under state command and control. At a July hearing before the House Armed Services Committee, Defense Secretary Mark Esper admitted that the thousands of out-of-state National Guard units deployed this summer to help subdue Black Lives Matter protests in DC also reported to a federal chain of command, rather than reporting solely to their governors. That violates the Posse Comitatus Act. (And Congress has not authorized any DC-specific exception). As Steve Vladeck has written, if the federal government relies on Title 32 authorities as a “kind of ersatz Title 10 status,” it would set an “ominous precedent.” Of the eleven states that sent in their National Guards to DC, ten have Republican governors; at least five Democrat-led states refused. Come November, Trump could again try to use § 502(f) to send in National Guard units from “friendly” Republican-led states into blue states. He cannot raise such a “red army,” however, without violating constitutional and posse comitatus principles.
Militarized Federal Agents
In July 2020, President Trump and DHS purported Acting Secretary Chad Wolf sent armed federal agents under “Operation Diligent Valor” to, in Trump’s own words, “quell” the protests and “take over” Portland–though the legal authorities that DHS cited were narrower than this rhetoric. Nevertheless, these agents wore military fatigues, carried military-style gear, and acted like an army occupying a hostile country: they used tear gas, rubber bullets, bean bags, pepper spray, flash-bang explosives; and unidentified agents arrested protesters in unmarked vans, reminiscent of renditions by secret police in authoritarian countries.
Despite wearing camouflage and carrying military-grade weapons, DHS agents are civilians, not the military, and therefore the Posse Comitatus Act does not apply. Indeed, avoiding the constraints of the Posse Comitatus Act makes DHS a particularly strong candidate for the president’s chosen vehicle for militarized law enforcement. The president, however, still runs into two constraints.
First is the constraint that applies to all executive power: the president has only the powers granted by the Constitution and Congress. The president does not have any inherent authority to command a standing force of armed civilian agents. Instead, a president can only order agencies to act within their statutory authority, and that authority is bounded by the Constitution.
Second, the president is constrained by the federalist system: the Tenth Amendment reserves to the states all powers that the Constitution does not otherwise delegate to the federal government, including a generalized police power. Thus, the president can deploy federal agents only to serve as law enforcement in a manner authorized by statute.
Here, the statute that Trump and Wolf claim authorizes them to send agents to Portland and other cities, 40 U.S.C. § 1315, does not authorize the activities for which they were invoked. That section permits the DHS Secretary to deploy DHS agents “for duty in connection with the protection of [federal] property . . . including duty in areas outside the property”—but only “to the extent necessary to protect the property and persons on the property (emphasis added).” In Portland, DHS agents were clearly and intentionally acting well beyond “the extent necessary” to protect federal property and persons on that property. That makes their actions—and DHS’s policy of deploying these agents in this manner—illegal.
If Trump and Wolf export the same tactic to other cities—as they have threatened to do—that would be illegal as well. As litigation that Protect Democracy filed argues, this statute simply does not authorize Trump to have a standing private army to invade cities he dislikes; it only authorizes federal agents to protect federal property and the persons on the property. Should Trump and Wolf attempt to deploy DHS agents under a different statutory authority in a different city, they would still be constrained by the specific limits of whichever statute they rely upon.
Trump and Wolf’s deployment of militarized DHS agents to Portland—and any future attempts to do the same in other cities—also violate the Constitution. The Constitution protects the right of protesters to protest, and to be free of unlawful retaliation for their protests. If Trump and Wolf send in militarized federal agents to punish protesters for their beliefs—and to punish cities or states that are seemingly aligned with the protesters—that would violate the First Amendment. That’s what happened in Portland; and it’s what Trump has threatened in other cities. Similarly, arresting protesters without probable cause—which, according to news reports, happened in Portland—violates the Fourth Amendment. And using excessive force such as tear gas, rubber bullets, flash bangs, and other violent tactics against protesters without provocation also violates the Fourth and Fifth Amendments.
For cities and states trying to fight back against this abuse of federal power, the Administrative Procedure Act (APA) provides a powerful litigation tool. The APA creates an explicit cause of action, and requires a court to enjoin any final agency action that is “contrary to law,” that is, that violates a federal statute and/or the Constitution. It thus provides a useful cause of action for protesters, cities, or states to use to sue the government for policies like DHS’s policy in Portland.
Patrolling the Polls or Interfering With Voting
Deploying armed federal agents—whether military or civilian—to polling places is itself illegal. This is above and beyond the specific ways that each of President Trump’s attempts to deploy a private army—whether the military, the National Guard, or civilian federal agents—are themselves illegal.
As noted above, there are a set of criminal laws that prohibit armed federal officials—whether civilian or military—from being deployed at or near polling places or interfering with an election in any way.
Beyond these criminal laws, there are three important federal statutes that explicitly prohibit intimidating voters, whether the intimidation is done by federal law enforcement, state law enforcement, private individuals, or anyone else. The oldest of these, the Ku Klux Klan Act of 1871 (now codified at 42 U.S.C. § 1985(3) clauses 3 and 4), prohibits conspiracies to intimidate or injure voters, whether by private or government actors. Section 131(b) of the) of the Civil Rights Act of 1957 and Section 11(b) of the Voting Rights Act both also prohibit voter intimidation by private and government actors. Moreover, a federal criminal statute, 18 U.S.C. § 594, makes voter intimidation a crime. Any attempt by Trump (or Wolf, or another federal official) to deploy the military or armed federal agents to a polling place, or near a polling place in a manner that is likely to intimidate voters or interfere with the election, would likely run afoul of these laws.
More broadly, the Fifth Amendment requires that elections be fundamentally fair, and that government officials not use their official powers over the electoral process to influence the outcome in a self-interested fashion. The First, Fifth, and Fourteenth Amendments also require federal and state officials to use their law enforcement powers in a non-partisan, non-arbitrary fashion, and prohibit the vindictive use of those powers against political opponents or in retaliation for constitutionally protected activities such a political speech, association, and voting. As the Seventh Circuit has recognized, “the power of government” cannot be “brought to bear . . . merely because a powerful . . . official harbors a malignant animosity.” As a result, if President Trump’s “motivation” for using law enforcement “was an unconstitutional one—e.g., if the reason for [doing so] was to chill the exercise of” constitutional rights, that too would violate the Constitution.
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In Youngstown Sheet & Tube Co. v. Sawyer, Justice Robert Jackson observed that no doctrine could be “more sinister and alarming” than to allow a president to “vastly enlarge his mastery over the internal affairs of the country by his own commitment of the Nation’s armed forces to some foreign venture.” Even more sinister and alarming would be to allow the president to influence the election through his command of armed forces, whether military or civilian, in some domestic venture. Given this president’s record, however, it is not an unlikely scenario. To safeguard a free and fair election this fall, decision-makers within government must adhere to their oaths to uphold the Constitution, and the courts, if called upon, must be willing to intervene to judicially safeguard our democracy. And the press and the public must be informed so as to understand what is illegal and illegitimate, and take direct action, through mass peaceful protests and other means, if necessary to safeguard our democracy.
Editor’s note: This article has been updated to remove reference to a historical connection between the National Guard and the Second Amendment provision for a “well-regulated Militia.”