On Saturday night, U.S. President Donald Trump federalized 2,000 soldiers from the California National Guard and deployed them to Los Angeles, with orders to “temporarily protect” federal Immigration and Customs Enforcement personnel, as well as other government personnel and federal property in the city. The move followed minor clashes between ICE as well as other federal security agencies involved in Trump’s mass deportation program and local community members in Los Angeles over the weekend.
National Guard troops are state-based members of the U.S. military that are under the command of state governors unless federalized. They are normally used to assist in responding to natural disasters as well as to restore and maintain order when local law enforcement is overwhelmed. Even so, they are most often federalized at the request of the governor due to the additional support and money that federal control can bring. The last time they were federalized without the governor’s consent, as is the case today, was in the 1960s to ensure compliance by southern states with federal civil rights protections for Black Americans.
Despite warnings from California Gov. Gavin Newsom that federalizing the guard was in this case unnecessary and would further inflame the situation—a warning that proved prescient—Trump doubled down on it, mobilizing an additional 2,000 National Guard soldiers as well as 700 active-duty Marines based in the state yesterday.
Observers of civil-military relations as well as legal experts have long worried that Trump may try to deploy the military domestically against Americans. Trump’s actions since the weekend have confirmed those fears, while raising new ones about the potential for abuses of power. They not only undermine the rule of law and raise a red flag for U.S. democracy but also threaten the relationship between American society and the military.
The move first and foremost stretches the limits of presidential authority. The Posse Comitatus Act of 1878 explicitly prohibits the president from deploying the military domestically to perform law enforcement functions, with a few exceptions. The law has ignominious origins—it was proposed and passed by southern Democrats who wanted to end the Army’s role in civil rights enforcement during the Reconstruction period following the Civil War. But it has nevertheless formed the bedrock of Americans’ understanding of the role of the military and is particularly important today. While in the early days of the republic it was necessary to call upon the Army to enforce law and order because of a lack of policing capacity, today’s state and local law enforcement are some of the most capable and well-resourced in U.S. history.
If the Trump administration deploys military forces to cities beyond Los Angeles, it lays the groundwork for abuses of power that will polarize public opinion about the military and very possibly galvanize opinion against it.
The main exception to the Posse Comitatus Act is the Insurrection Act, which is actually a series of laws passed in the 18th and 19th centuries that outline the—arguably broad—conditions under which the president can legally deploy federal forces to perform domestic policing operations. The details and logistics of chains of command under such circumstances get complicated, but the general sentiment is relatively straightforward: Law enforcement inside the U.S. is intended to be a matter for state and local authorities, not the federal government. States have their own laws, ordinances and standards of practice that military members are unfamiliar with and unprepared to enforce. The use of as blunt an instrument as active-duty military, or National Guard troops under the command of the president, is therefore supposed to be a last resort. Historically, invoking the Insurrection Act is extremely rare—it has only been done 30 times in all of U.S. history, and as a result it comes with political costs.
It is noteworthy that Trump has not yet officially invoked the Insurrection Act. Instead, the administration is relying on a section of the U.S. Title 10 Code, Section 12406, that allows the president to deploy forces to protect federal assets. Not only is the justification for using this code alone—rather than in combination with the Insurrection Act, as has historically been the case—completely unprecedented, it is legally dubious.
What’s more, even if the administration had invoked the Insurrection Act, the Executive Order it is using to federalize the California National Guard is not geographically limited to California. Rather, it purports to authorize the use of the military wherever protests may occur, making it a preemptive authorization to do so anywhere in the United States. This itself sets a dangerous precedent, as previous uses of the Insurrection Act have all been geographically defined. Even then-President Abraham Lincoln’s invocation of the act during the Civil War was limited to the southern states in rebellion.
These two features—the reinterpretation of U.S. law to justify the independent deployment of military forces and the lack of limits on where they may be employed—create the potential for a massive abuse of power. If allowed to stand, they effectively pave the way for the administration to use military force against American citizens anywhere on U.S. soil.
This is not the first time that the Trump administration has sought to use emergency powers to justify extremely broad interpretations of federal authority in legally dubious ways, or the first time that it has involved the military to facilitate legally dubious actions. Notably, however, it is the first time it is attempting to use the military’s coercive power, as opposed to its logistics capabilities, in the service of its domestic political goals.
In addition to the clear challenges the administration’s actions pose to rule of law in the U.S., they further violate important civil-military norms and jeopardize the military’s relationship with the broader U.S. society in important ways. The deployment to Los Angeles involves the military in a highly controversial and already politicized immigration operation; puts service members in a situation for which they receive little to no training; and puts military leaders in the middle of a political fight between the president and a state governor. The effect, especially if it is reproduced elsewhere, will be to further politicize the military and undermine public confidence in it as an institution, which research suggests could have downstream effects on recruitment, retention, morale and the overall professionalism of the force.
Indeed, while the public has historically tolerated the deployment of National Guard forces during times of civil unrest as they work to restore law and order, local residents don’t remain supportive if military forces are seen as contributing to the chaos rather than quelling it. And if the Trump administration does choose to use its Executive Order to deploy military forces to cities beyond Los Angeles, it lays the groundwork for abuses of power that will polarize public opinion about the military and very possibly galvanize opinion against it.
Already some political actors have begun to push back in positive and constructive ways. Newsom has already brought a lawsuit against the Trump administration, which will likely clarify the president’s authorities under section 12406 and publicize the ways in which the Executive Order as issued could lead to profound abuses of power. Growing demonstrations in Los Angeles and solidarity protests that have already sprung up elsewhere will shape public opinion about the use of the military in domestic situations and—to the extent that they remain peaceful—probably drive opposition to the administration’s moves. And retired military leaders, along with experts on civil-military relations, have begun to speak out about the misuse of military resources for domestic law enforcement operations.
Yet Congress must also get involved. As others have pointed out, these operations cost money, and congressional leaders should exert control and oversight over how federal dollars are spent on them. Service members must also be informed about the nuances of operating within the U.S., and military leaders have an obligation to provide strict and clear rules of engagement in order to mitigate harm and prevent escalation.
The Trump administration has once again pushed civil-military relations to the brink, this time by using military power to undermine state officials’ authority and further politicize already controversial operations. If its actions are not appropriately contested and reversed, the consequences could be profound and have lasting impacts on the military’s relationship with the American people.
Carrie A. Lee is a senior fellow with the German Marshall Fund of the United States and visiting scholar with the University of Pennsylvania’s Perry World House. From 2021 to 2025, she served as chair of the Department of National Security and Strategy at the U.S. Army War College.