And you thought Nancy Pelosi’s speech-tearing at the State of the Union address ripped Washington apart…

Mitt Romney became the first Senator in U.S. history to vote to convict a president of his own party on Wednesday, as the lone Republican to side with Democrats in voting Donald Trump guilty of the first article of impeachment: abuse of power. He returned to his party’s side to acquit Trump of the second article, obstruction of Congress.

Read more: Trump acquitted by Senate, ending historic impeachment trial

“I am sure to hear abuse from the president and his supporters,” Romney said in his emotional speech on the Senate floor Wednesday, explaining that his faith and his conscience drove him to cast the dissenting vote.

He could say that again. Retribution from the Republican party — including the Trump family and Romney’s own niece — was swift.

At Thursday morning’s National Prayer Breakfast, President Trump didn’t mention Romney by name, but said, “I don’t like people who use their faith as justification for doing what they know is wrong.” Later on he added, “We have allies, we have enemies, sometimes the allies are enemies but we just don’t know it.”

Read more: Trump rips ‘very unfair’ impeachment effort as he celebrates acquittal at White House

He also tweeted a video that called Romney “slick, slippery, stealthy.”

On Twitter TWTR, +16.80%, Trump called Romney a “failed presidential candidate,” and mocked his loss to a “faltering Barack Obama” in 2012.

The “failure” taunt was picked up by other Republicans, including White House press secretary Stephanie Grisham. “Only the president’s political opponents — all Democrats, and one failed Republican presidential candidate — voted for the manufactured impeachment articles,” she said in a statement released after the president was acquitted.

House Minority Leader Kevin McCarthy (R-Calif.) wrote, “Mitt’s flat wrong on this, and he doesn’t represent the views of any Republican in Congress.”

“This is not the first time I have disagreed with Mitt, and I imagine it will not be the last,” chimed in his niece and GOP chairwoman Ronna McDaniel.

His home state Utah Republican Party also disagreed with him, tweeting that it was “pleased” to see the president acquitted, and, “as a party, we strongly disagree with the vote cast today by Senator Romney.”

Meanwhile, Donald Trump Jr. called Romney “officially a member of the resistance,” and said he should be “expelled” from the Republican Party.

And many Trump supporters called him a “traitor” and “Benedict Romney,” jeering that he just destroyed his career.

But Jeff Flake, a former Republican senator from Arizona, expressed his admiration for Romney’s vote.

Romney noted that this wasn’t an easy vote for him. “I knew from the outset that being tasked with judging the president, the leader of my own party, would be the most difficult decision I have ever faced. I was not wrong,” Romney said in his speech Wednesday.

But, “were I to ignore the evidence that has been presented, and disregard what I believe my oath and the Constitution demands of me for the sake of a partisan end, it would, I fear, expose my character to history’s rebuke and the censure of my own conscience.”

Across the aisle, Democrats and critics of the administration were hailing Romney as an “American hero” for putting his country above his party, and arguing he will fall on the “right” side of history.

Stephen Colbert thanked Romney in his “The Late Show” monologue “for serving the Constitution rather than that monstrous child in the White House.”

The Salt Lake Tribune’s editorial board also praised him for “doing the right thing,” noting, “Mitt Romney could have ducked this one … regardless of politics, ideology or religion should be duly impressed with Romney’s decision to follow his heart and his conscience — and his God — in doing the right thing when doing the right thing was difficult.”

Senator and Democratic presidential candidate Elizabeth Warren called Romney’s vote “an act of patriotism,” while fellow 2020 candidate Andrew Yang told CNN that “I just want to congratulate Sen. Mitt Romney for voting his conscience and character.”