Donald Trump Jr. lashed out at Sen. Mitt Romney on Wednesday after the Utah Republican announced he would vote to convict in the Senate impeachment trial.

The president’s son made the remarks after Romney announced his decision on the Senate floor.

“Mitt Romney is forever bitter that he will never be POTUS,” the president’s son wrote on Twitter. “He was too weak to beat the Democrats then so he’s joining them now.”

“He’s now officially a member of the resistance & should be expelled from the @GOP,” he added.

Mitt Romney is forever bitter that he will never be POTUS. He was too weak to beat the Democrats then so he’s joining them now.

He’s now officially a member of the resistance & should be expelled from the @GOP.

— Donald Trump Jr. (@DonaldJTrumpJr) February 5, 2020

UPDATE: Not to mention this bit of class from Don Jr.