President Trump issued a memo authorizing the National Guard to post up in Los Angeles, but California Gov. Gavin Newsom has called it "illegal."

Trump has not invoked the Insurrection Act, which is the main legal tool a president can use to activate the military or National Guard when there is rebellion or unrest. But he hasn’t ruled it out, either. “Depends on whether or not there’s an insurrection,” Trump told reporters Sunday after a question about invoking the Insurrection Act.

California Governor Gavin Newsom, a Democrat, told MSNBC that he plans to file suit Monday against the Trump administration to roll back the National Guard deployment, which he called “an illegal act,