United States President Donald Trump's threat to invoke a federal anti-insurrection law to expand his deployment of military personnel to US cities has intensified his legal battle with Democratic-led cities over presidential authority, as hundreds of national guard troops from Texas prepare to patrol the streets of Chicago.
The president said on Tuesday (AEDT) he would consider utilising the Insurrection Act, a law enacted more than two centuries ago, to sidestep any court rulings restricting his orders to send national guard troops into cities over the objections of local and state officials.
"We have an Insurrection Act for a reason," said Trump, who has claimed troops are needed to protect federal property and personnel in carrying out their duties, as well as assisting an overall drive to suppress crime.
"If people were being killed and courts were holding us up, or governors or mayors were holding us up, sure, I'd do that."
"If you look at Chicago, Chicago is a great city where there's a lot of crime, and if the governor can't do the job, we'll do the job. It's all very simple."
The law, which gives the president authority to deploy the military to quell unrest in an emergency, has typically been used only in extreme cases, and almost always at the invitation of state governors.
The act was last invoked by former US president George HW Bush during the Los Angeles riots of 1992.
An exception to the rule
Under federal US law, national guard and other military troops are generally prohibited from conducting civilian law enforcement. But the Insurrection Act operates as an exception to that rule and would give troops the power to directly police and arrest people.
Using the act would represent a significant escalation of Trump's campaign to deploy the military to Democratic cities, an extraordinary assertion of presidential power.
Last week, in a speech to top military commanders, Trump suggested using US cities as "training grounds" for the armed forces, alarming Democrats and civil liberties groups.
Randy Manner, a retired US Army major general who served as acting vice chief of the National Guard Bureau, said using the Insurrection Act in the way Trump appears to be contemplating has no real precedent.
"It's an extremely dangerous slope, because it essentially says the president can just do about whatever he chooses," said Manner, who served under both Republican and Democratic administrations before retiring in 2012.
Trump has ordered national guard troops to Chicago, the third-largest US city, and Portland, Oregon, following his earlier deployments to Los Angeles and Washington DC.
In each case, he has done so despite staunch opposition from Democratic mayors and governors, who say Trump's claims of lawlessness and violence do not reflect reality.
In Chicago and Portland, protests over Trump's immigration policies had been largely peaceful and relatively limited in size, according to local officials.
Since Trump sent federal agents to the Chicago area last month, residents have responded with mostly small demonstrations.
In most of Chicago, people have commuted to work, gone to the theatre and flocked to beaches to enjoy unseasonably warm weather in a city where violent crime has fallen sharply — far from the "war zone" conditions Trump has described.
Protests have been much less disruptive than the unrest in 2020 triggered by the death of George Floyd, an unarmed Black man, at the hands of Minneapolis police officers.
The most regular demonstration has taken place outside an immigration processing facility in the Broadview suburb, where up to several dozen people have been engaged in increasingly violent standoffs with federal immigration officers, who have fired tear gas and rubber bullets from the roof of the facility at protesters.
Several people, including at least one reporter, have been arrested, and dozens of people have been injured by the agents' chemical munitions.
Trump accused of using troops as 'political props and pawns'
Illinois governor JB Pritzker, a Democrat, accused Trump of intentionally trying to foment violence in Chicago, which the president could then use to justify further militarisation.
"Donald Trump is using our service members as political props and as pawns in his illegal effort to militarise our nation's cities," Pritzker told reporters on Monday.
Illinois and Chicago sued the Trump administration on Monday, seeking to block orders to federalise 300 Illinois national guard troops and send 400 Texas guard troops to Chicago. During a court hearing, justice department lawyers told a federal judge that hundreds of Texas guard troops were already in transit to Illinois.
The judge, April Perry, permitted the deployment to proceed for now but ordered the US government to file a response by Wednesday.
Separately, a federal judge in Oregon on Sunday temporarily blocked the administration from sending any national guard troops to police Portland, the state's largest city.
National guard troops are state-based militia who normally answer to the governors of their states and are often deployed in response to natural disasters.
During Trump's deployments to various cities, the national guard has been limited to protecting federal agents and property, though the US defence department has said troops have the authority to detain people temporarily to prevent immediate harm.
A federal judge ruled last month that troops in Los Angeles overstepped their authority by controlling crowds and blocking traffic. The Trump administration has argued those actions were legal to protect federal agents conducting immigration raids and has appealed the decision.
Any effort by Trump to invoke the Insurrection Act would also likely face legal challenges. The law has rarely been interpreted by the courts, but the Supreme Court has ruled that the president alone can determine if the act's conditions have been met.
Those conditions include when the US government's authority is facing "unlawful obstructions, combinations or assemblages or rebellion."
The act, a version of which was first enacted in 1792, has been used by past presidents to deploy troops within the US in response to crises such as the 1794 Whiskey Rebellion and the rise of the Ku Klux Klan after the American Civil War.
But the last time another president deployed the national guard in a state without a request from the governor was 1965, when then-president Lyndon Johnson sent troops to protect civil rights demonstrators in Montgomery, Alabama.
