George Floyd protests: can Trump deploy federal troops on to the streets in the US?

Sam Levin
Photograph: Chip Somodevilla/Getty Images

US president Donald Trump has threatened to deploy the United States military to American cities to quell civil unrest in the wake of George Floyd’s death.

Speaking in the White House’s Rose Garden as a series of military vehicles rolled out front on Pennsylvania Avenue and military police and law enforcement clashed with protesters at Lafayette Park, Trump declared himself the president of law and order. But does he have the power to carry out his threats?

Under the civil war-era Posse Comitatus Act, federal troops are prohibited from performing domestic law enforcement actions such as making arrests, seizing property or searching people, the AP notes.

Related: US cities see fresh protests after George Floyd's death ruled homicide

In extreme cases, however, the president can invoke the 1807 Insurrection Act, also from the civil war, which allows the use of active-duty or National Guard troops for law enforcement.

According to CNN, the law was most notably used in the 1950s to enforce desegregation. And later, in the 1960s, to address riots in Detroit. The Congressional Research Service said it hasn’t been invoked since 1992 during the riots in Los Angeles that followed the acquittal of four white police officers in the beating of Rodney King, it said.

In the Atlantic last year, when there was talk of Trump using this act for immigration enforcement, Stephen I Vladeck, a professor of law at the University of Texas, wrote: “The ‘Insurrection Act’ is an umbrella term for a series of statutes that date all the way back to the Founding, and through which Congress has exercised its authority under Article I, Section 8, Clause 15 of the Constitution ‘to provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions’.

“The Constitution’s drafters understood that there would be circumstances in which local authorities were inadequate to protect the populace and enforce the laws, and so went out of their way not only to identify three circumstances in which troops could be used, but also to give the power to delimit those circumstances to Congress, not the president.”

One crucial Supreme Court opinion, Vladek noted, said: “Congress, not the Executive, should control utilization of the war power as an instrument of domestic policy.”