PORTLAND, Ore. (AP) — Attorneys for Oregon argued Wednesday for a restraining order against federal agents deployed to quell protests in Portland — a standoff that some legal experts have warned could lead to a constitutional crisis in an election year.

A federal judge heard arguments from the state and the U.S. government in a lawsuit filed by Oregon Attorney General Ellen Rosenblum, who accuses federal agents of arresting protesters without probable cause, whisking them away in unmarked cars and using excessive force. Federal authorities have disputed those allegations.

The lawsuit is part of the growing pushback to President Donald Trump sending federal agents to Portland and announcing they’d also be going to Chicago and Albuquerque, New Mexico, to fight rising crime, a move that’s deepening the country’s already considerable political divide. Democratic mayors of 15 cities condemned the use of the agents in a letter to the U.S. attorney general.

The court hearing focused on the actions of more than 100 federal agents responding to protests outside Portland’s Mark O. Hatfield Federal Courthouse, which has been a target for more than 50 nights of demonstrations against racial injustice following the killing of George Floyd at the hands of Minneapolis police.