President Trump on Thursday slammed Rep. Justin Amash as a “total loser” — cheering the Michigan lawmaker’s decision to quit the GOP.

“Great news for the Republican Party as one of the dumbest & most disloyal men in Congress is ‘quitting’ the Party. No Collusion, No Obstruction!” Trump tweeted hours after the 39-year-old libertarian announced his move in a Washington Post op-ed.

“Knew he couldn’t get the nomination to run again in the Great State of Michigan. Already being challenged for his seat. A total loser!” the president added.

Amash faced two primary challenges after saying in May that Trump committed impeachable offenses — and that Attorney General William Barr had “deliberately misrepresented” special counsel Robert Mueller’s report on Russian meddling in the 2016 election.

The president has previously called Amash “a total lightweight” and “a loser who sadly plays right into our opponents hands!”