In 1791, a United States Army detachment pursuing war against Native Americans in the Northwest Territory — today known as Ohio — suffered a catastrophic defeat. By the end of the affair, now known as the Battle of Wabash, half of the United States’ already tiny and ill-equipped army was gone.
Informed of reports of the military’s inadequacy, Congress responded by passing the Militia Act of 1792, which permitted the President to use state militias against “an insurrection in any state, against the government thereof”. The wording of the Militia Act not only gave executives a firmer hand in dealing with foreign nations like the tribes of the Northwest Territory but also in quelling home-grown insurgencies. Two years later, just before the act expired, President George Washington invoked it to quash the Whiskey Rebellion of 1794.
Congress then passed the even more stringent Insurrection Act of 1807, which President Trump has floated the possibility of invoking in order to quell the current protests against police brutality. In the most literal sense, the 1807 Act simply strengthened the previous Militia Acts by giving the President the authority to call forth the federal U.S. Army and Navy in addition to state militias. But this crucial addition is partly why the 1807 Act is being discussed in executive circles today. Unlike the previous Militia Acts, which relied on the consent and cooperation of state governments, the Insurrection Act specifically provides for cases in which state governments are “unable or unwilling” to enforce law and order.
This provision is taking on a new urgency as state officials in both political parties favour softer tactics in the face of massive Black Lives Matter protests and, to a much lesser extent, incidents involving looting or the destruction of property. Theoretically, Trump can invoke the Act and use the force of the U.S. military to suppress unrest without the permission of the states.
It would not be the first time the Act has been invoked on U.S. soil. One year after it was passed, President Jefferson used it to suppress disorder on Lake Champlain. Since then, the federal government has routinely used armed forces to quell unrest, including opposition to segregation in the South during the 20th Century civil rights movement. Most recently, the Act was used during the 1992 Los Angeles riots in response to another incident of police brutality against Rodney King.
However, there are several roadblocks which stand in Trump’s way. Some legal analysts have posited that the Posse Comitatus Act, which limits the ability of the federal government to use the military to preserve law and order, is one such hurdle. The 1878 Act was passed as part of broader measures intended to end Reconstruction, to hinder attempts to provide improved rights and living conditions for black Americans in the post-Confederacy South.
Although, the Posse Comitatus Act is not watertight, and in fact allows the President to call forth the military if they “determine that the use of the Armed Forces is required to fulfill the President’s obligations under the Constitution to respond promptly in time of war, insurrection, or other serious emergency.”
Yet many scholars believe that the current circumstances do not meet the required preconditions for the invocation of the Insurrection Act. For one, President Trump is not arguing that states are unable or unwilling to enforce the law. Daily clashes, often violent, between local police officers and demonstrators underline this point.
Rather, the President seems to believe that an overwhelming show of force by the US military will end the unrest more quickly. Most governors have explicitly rejected any idea of requesting military assistance from the President. However, Republican Senator Tom Cotton of Arkansas, perhaps demonstrating a greater understanding of the law, argued in a widely-criticised New York Times op-ed that the situation is serious enough to warrant an invocation of the Insurrection Act, even without the consent of local officials.
It seems like the validity of the Insurrection Act is in some sense political. Using military force on domestic soil has historically been deeply unpopular, which goes some way towards explaining why it has not been invoked in almost three decades. Additionally, some of President Trump’s own cabinet officials have made rare public gestures of defiance in response to the possibility of the Act being used. Therefore, it seems unlikely that the President will try to use the 200-year-old legislation. Nevertheless, the public debate over the limits of executive military authority on domestic soil may become even more salient as the nation is increasingly at odds with its leadership.