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, an immoral act, an unconstitutional act.”

Trump has cited a legal provision that allows him to mobilize federal service members when there is “a rebellion or danger of a rebellion against the authority of the Government of the United States.”

Trump threatens to arrest Newsom: “I would do it if I were Tom. I think it’s great,” Trump said, referencing Tom Homan, the administration’s border czar, who warned that anyone, including public officials, would be arrested if they obstructed federal immigration enforcement. “Come after me, arrest me. Let’s just get it over with, tough guy,” Newsom said.