There’s growing concern that President Donald Trump might invoke the Insurrection Act to bring National Guard troops under federal control and deploy them within the U.S. This speculation may be partly because one of President Trump’s Inauguration Day executive orders, which declared a national emergency at the southern border set an April 20 deadline for the Departments of Defense and Homeland Security to recommend whether to use the Insurrection Act. That date is approaching quickly.
Make no mistake: If Trump invokes the Insurrection Act to activate federalized troops for mass deportation—whether at the border or somewhere else in the country—it would be unprecedented, unnecessary, and wrong. But the president has already been increasing domestic military use. As recently as April 11th, he issued a new memorandum with yet another chill-inducing title: “Military Mission for Sealing the Southern Border of the United States and Repelling Invasions.” It’s worth repeating that there is no invasion of America, and if President Trump doubts that, he could consult himself. Last month he declared on Truth Social that the (fictional) “Invasion of our Country is OVER.” Yet under his new directive, the Defense Department is claiming new and potentially expansive powers over large swaths of federal land—including where US citizens and other border residents live. .
Let’s step back a bit first and recall the military’s proper, limited role on U.S. soil, and the dangerous steps President Trump is already taking in service of his cruel anti-immigrant, anti-American agenda.
When the Founders drafted the Constitution, they were concerned about constraining a rogue executive, preventing a standing (i.e. large and permanent) army, ensuring civilian government and a nonpartisan military, and safeguarding civil rights and civil liberties. From then until now, we know that a core component of liberty and democracy is the strong presumption against military enforcement of civil law—put simply, the military should not be policing civilians.
For these reasons, even when the Founders and Congress have given the president war and emergency powers, it is with constraints. For example, the Posse Comitatus Act of 1878 makes it a crime to use federal military forces “to execute the law,” except when “expressly authorized” under the Constitution or by an act of Congress. In practice, this means that the Defense Department generally forbids federal troops from carrying out direct civilian law enforcement activities on U.S. soil such as surveillance of individuals, questioning and interrogations, arrests, searches, and seizures, among other things.
Another key principle is civilian control over the military, which means that military troops must follow a president’s lawful orders. Troops don’t get to pick and choose which lawful civilian orders they follow and which they don’t. But for this system to work, presidents and military leaders must be careful to ensure that the orders they give are unambiguously lawful. Otherwise, they put troops at legal and ethical risk, weaken military cohesion, and undermine the constitutional design, which prevents direct military involvement in civilian life, except in the limited circumstance of genuine crises.
Nor should the military act—or appear to act—in service of a partisan political agenda. Domestic deployment of the federal military is rare and has historically been reserved for genuine emergencies, like the extreme situation of an actual war, an armed rebellion, or to enforce federal laws if civilian agencies and courts aren’t functioning. One clear example comes from 1958, when President Dwight D. Eisenhower invoked the Insurrection Act (which is an exception to the Posse Comitatus Act) and deployed federal troops to Arkansas to enforce the Supreme Court’s Brown v. Board decision and guard the Little Rock Nine against a racist and violent mob. President Eisenhower acted after then- Governor Orval Faubus had deployed the state National Guard to support segregationists in defiance of the Supreme Court’s decision.
The Constitution also allocates power between the federal government and the states, generally imposing on the federal government the duty to enforce federal law and defend against truly extreme crises and emergencies, while reserving police powers to the states. Normally, National Guard troops are maintained by states, under the command of their governors, as explained below. States have a critically important role to play in ensuring lawful and appropriate use of police powers within their state while safeguarding individual civil liberties and rights.
Applying these principles, here are the key things to know about how domestic military deployment normally works:
States’ National Guard Deployment
Federal Role in National Guard Deployment
Congress has enacted laws governing both federal military and National Guard deployment and conduct in Titles 10 and 32 of the U.S. Code.
On Inauguration Day, Trump declared a national emergency at the southern border, falsely claiming an invasion, and authorized a dramatic increase in the number of federalized National Guard troops deployed to the border under Title 10. Since then, he’s also sent combat vehicles to our border communities. So far, Trump’s domestic troop deployment has been limited to support for border operations. Troops have been supporting border wall construction and materials transportation, monitoring and detection assistance, and providing logistical assistance for civilian agencies like Immigration and Customs Enforcement (ICE) and Customs and Border Protection (CBP).
But his actions are worsening the conditions under which civilian border communities live. Our southern border is home to approximately 19 million people, in addition to the regular business and trade commuters who come across the border every day. In recent years, U.S. citizens and other border residents have been exposed to intrusive civilian law enforcement surveillance, aggressive federal policing, border patrol checkpoints they must pass through for medical care and daily activities, and environmental degradation from border wall construction. Border patrol agents have engaged in deadly vehicular pursuits and excessive use of force against border residents, and in one of his initial executive orders, President Trump revoked the 2023 Customs and Border Protection policy to limit these deadly chases.
On April 11, Trump issued a memorandum giving the Defense Department use and jurisdiction over public civilian lands along the border—including the Roosevelt Reservation in New Mexico and excluding Federal Indian Reservations—for military activities. Trump’s directive allows the secretary of defense to identify “military activities that are reasonably necessary and appropriate” including actions to “protect and maintain the security of military installations” and exclude people from newly designated “national defense areas.” In other words, Trump is opening the door to an expanding military role that goes beyond logistical support—and potentially beyond the identified zone.
The new policy has serious implications for border residents living under this expanded militarized zone, which includes cities like San Diego, CA; Nogales, Arizona; El Paso, Texas and other heavily populated, thriving communities. People in these areas could now face federal prosecution for trespassing if they unintentionally walk or drive onto a designated “national defense area.”
Given the numerous documented cases of excessive use of force by border patrol agents, we are deeply concerned about the potentially dangerous consequences of adding more armed troops to border communities, in an environment that military personnel may not be trained for. Trump’s new memorandum states that “members of the Armed Forces will follow rules for the use of force prescribed by the Secretary of Defense,” but these rules may be completely inappropriate for densely populated, civilian areas.
President Trump has not invoked the Insurrection Act—yet. But his administration continues to invest in the theatre of war, like wrongly invoking wartime authorities such as the Alien Enemies Act, and threatening drone strikes against drug cartels in Mexico. None of this makes us safer, and this latest move to hand over public land to the military forces our civilian communities to live in fear.
Right now, we are calling on members of Congress to insist on oversight for these expanded actions—in particular, any changes to rules governing use of force—and to call for safeguards and transparency to protect border residents from escalating military control over their daily lives.
These developments are bad enough. Invocation of the Insurrection Act is both unnecessary and would make them worse.
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Trump's Expanded Domestic Military Use Should Worry Us All – American Civil Liberties Union
