American Institutions Under Trump: The National Guard

In Trump’s America, much has recently been said about the National Guard. Twice already this summer, the president has deployed this military force in American cities: first in Los Angeles, then in Washington, the federal capital, officially to “maintain order” and “combat crime”. On social media, Trump even threatened to send troops to other cities — all governed by Democratic mayors — for the same reasons. This week, Trump again raised the possibility of deploying the Guard in the city of Chicago. But what exactly is the National Guard? Does the Constitution really allow the use of military forces to carry out civilian policing missions? In short, does Trump actually have the right to do this?

The answers to these questions are rather complex, rooted in the federal structure of the U.S. system.

The National Guard is a hybrid institution, under both state and federal authority. Its origins date back to the colonial era, well before independence, when each colony maintained its own militia. These militias, composed of citizens, were called up periodically to defend their communities against possible Native attacks or French incursions. When the United States was created, the new Constitution granted the federal government the power to call up each state’s militia “to execute the laws of the Union, suppress insurrections, and repel invasions.”

In modern times, the National Guard is made up of ground and air units, trained and equipped similarly to active-duty army units. Under normal circumstances, they are under the authority of their state governor and can be mobilised to respond to natural disasters or serious public disorder within their state. In 2024, for example, several states called up the Guard for civil protection missions during Hurricane Helene. In the event of a national crisis, the president can also mobilise the Guard, with or without the governors’ approval. In wartime, its units join the active-duty military: the 29th Infantry Division, composed entirely of National Guard reservists, landed on Omaha Beach on 6 June 1944.

Does the National Guard have a role to play in combating crime? The answer to this highly relevant question remains ambiguous. It is certain that the Guard can be mobilised to face serious threats to public order, and recent U.S. history offers several examples. The Minnesota National Guard, for instance, intervened during the 2020 “Black Lives Matter” protests after George Floyd was killed by police. But such use of the Guard is somewhat controversial: it first signals an admission of failure by local authorities, who are primarily responsible for public safety; and second, its units, rarely trained to manage civilian crowds, may resort too quickly to lethal force. The emblematic image of the Vietnam War protest movement bears this out: a kneeling protester, arms raised, beside the body of a fellow student shot dead by the Ohio National Guard at Kent State University in 1970. That day, the protest had been mostly peaceful despite some stone-throwing, and better-prepared police forces would likely not have opened fire on young students exercising their right to free speech.

The use of the National Guard to fight ordinary crime is far less certain. In principle, U.S. law prohibits the use of armed forces for policing functions: the “Posse Comitatus” Act of 1878 clearly states that, without explicit Congressional authorisation, the army has no role in this area. There is one exception, however: the National Guard can be called up to maintain public order, as mentioned, but only under the authority of the state governor — which excludes its use by the president. Another law, the “Insurrection Act” of 1807, exceptionally authorises the use of federal military forces in cases of rebellion. During his first term, the president threatened to invoke this law but ultimately did not.

Yet, since taking office, Donald Trump has “federalised” the National Guard twice for civilian policing missions, despite local opposition. How was this possible? In June, as protesters in Los Angeles opposed the new administration’s immigration policy, Trump claimed the city was “under siege” and sent 2,000 California National Guard troops. Officially, these troops were tasked with “protecting” buildings and federal agents, but they sometimes performed policing functions. The state’s Democratic governor, Gavin Newsom, strongly opposed this deployment and sued for violation of the Posse Comitatus Act. In September, a federal judge ruled in his favour and ordered the troops withdrawn. In Washington, Trump declared a “crime emergency” in a heavily Democratic city where violent crime rates are at their lowest in 30 years, and attempted to “nationalise” the capital’s police. Because of Washington’s special status — partially under federal authority and without a governor — the president could attempt such intervention more easily, but once again the courts ruled he had overstepped his powers.

So far, these two National Guard deployments, suspended by the courts, have likely caused no major damage. But how could these interventions — and any future deployments of military forces to other Democratic-run cities — pose a danger to the Republic?

First, they represent a highly political use of a national institution that is supposed to remain above any particular interest. The mobilisation of the National Guard, however performative, gives voters — especially those who pay little attention to politics — the misleading impression that Democratic authorities are utterly overwhelmed by crime in their cities and states: “Things are so catastrophic that Trump had to send in the troops!” they might think. This could significantly influence their choices in the midterm elections. More seriously, this use of military forces undermines democratic norms: the fact that the president, despite clear legislation, uses soldiers as police against his domestic political opponents is alarming. Finally, there is an ominous echo of civil war in these interventions. Six states led by Republican governors sent National Guard units to Washington. In a city where nearly half the population is Black, how must residents feel seeing their capital “occupied” against their will by soldiers from Mississippi or Louisiana? Even if Trump’s National Guard deployment in Washington divides public opinion, an August 2025 Reuters poll shows that 76% of Republicans support it, compared to only 8% of Democrats.