A group of big-city mayors on Tuesday formally asked "the big four" congressional leaders to investigate the Trump administration's deployment of federal law enforcement to quell protests in Portland, Oregon, and elsewhere.
"These forces are conducting crowd control on city streets and detaining individuals," they say in a letter. "Their threats and actions have escalated events, and increased the risk of violence against both civilians and local law enforcement officers."
The letter from 15 mayors, including Eric Garcetti of Los Angeles, Muriel Bowser of the District of Columbia, Keisha Lance Bottoms of Atlanta, and Ted Wheeler of Portland, was addressed to House Speaker Nancy Pelosi, D-California, House Minority Leader Kevin McCarthy, R-California, Senate Majority Leader Mitch McConnell, R-Kentucky, and Senate Minority Leader Chuck Schumer, D-New York.
The document sketches a pattern of deployment of federal agents and threats of further incursions in response to a wave of public dissent that began with the in-custody of death of George Floyd in Minneapolis May 25.
Mayor Bill de Blasio of New York City spoke in support of the letter on "Morning Joe" on Wednesday and warned against the Trump administration's sending any federal troops to his city.
“I believe what the president is doing is unconstitutional” in trying to suppress protests in Portland, de Blasio said.
"If one of these federal officers steps foot in New York City with the intention of denying the First Amendment rights of New Yorkers, we will be in court immediately, and we will win," the mayor said. "Every time the Trump administration has tried to bend the Constitution to their will they have lost in court."
Federal forces, including the National Guard and the U.S. Secret Service, were used to clear peaceful protesters from Lafayette Square in Washington, D.C. on June 1 just before President Donald Trump walked through the park en route to a photo op.
It was one of many demonstrations that swept the nation following Floyd's death. One of Trump's responses to protests, including some that transformed into unrest, was to threaten to use the military to calm them.
"I am mobilizing all available federal resources, civilian and military, to stop the rioting and looting, to end the destruction and arson and to protect the rights of law-abiding Americans, including your Second Amendment rights," Trump said on June 1.
However, on Tuesday, acting Homeland Security Secretary Chad Wolf said during a news conference that deployment of U.S. Customs and Border Protection agents and other federal forces in Portland was not a Trump executive order but simply routine.
He said the forces were policing protests as part of their duties to protect federal property. Recent demonstrations in Portland have targeted the area of a federal courthouse.
The same day, the president said more cities, including New York, Chicago, Philadelphia, Detroit, Baltimore, and Oakland, could see similar enforcement.
"We're not going to let this happen in our country," Trump said.
The president in mid-June also threatened to use the military to break up protesters' occupation of an area of Seattle known as the Capital Hill Autonomous Zone.
Leaders in Portland and across Oregon have argued the protests were dying down until recent days when the presence of federal forces incited wider demonstrations over the weekend.
The letter's signatories argued that the deployment has violated "fundamental constitutional protections and tenets of federalism" and called it an "abuse of power."
It asks congressional leaders to help the public understand what circumstances would justify using federal firepower against Americans.