A Michigan state lawmaker has announced plans to challenge Rep. Justin Amash in the Republican primary for the state’s 3rd District after the congressman broke with his party on impeaching President Donald Trump.

State Rep. Jim Lower, who describes himself on his campaign website as a “Pro-Trump” Republican, said in a statement that Amash “must be replaced, and I am going to do it.”

Amash, who was elected to the House in the 2010 GOP tea party wave and is a founding member of the hard-line conservative House Freedom Caucus, wrote in a Twitter thread on Saturday that he believes Trump has “engaged in impeachable conduct,” as outlined in the final report of special counsel Robert S. Mueller III.

He did not spare Attorney General William Barr either, concluding that Barr “intended to mislead the public” about Mueller’s report and banked on the notion that most Americans would not read it for themselves.

“Contrary to Barr’s portrayal, Mueller’s report reveals that President Trump engaged in specific actions and a pattern of behavior that meet the threshold for impeachment,” Amash tweeted Saturday.

“Mueller’s report identifies multiple examples of conduct satisfying all the elements of obstruction of justice, and undoubtedly any person who is not the president of the United States would be indicted based on such evidence,” he wrote. He defended his remarks with another series of tweets Monday afternoon. 

Here are my principal conclusions:
1. Attorney General Barr has deliberately misrepresented Mueller’s report.
2. President Trump has engaged in impeachable conduct.
3. Partisanship has eroded our system of checks and balances.
4. Few members of Congress have read the report.

— Justin Amash (@justinamash) May 18, 2019

Lower on Monday called Amash “out of touch” with West Michiganders.

The challenger had intended to announce his bid around July 4, but the congressman’s weekend Twitter thread prompted Lower to move up his timeline.

“Amash has not only failed to support President Trump as the president works to make the United States stronger and safer, he has now united with radical liberals like Democratic congresswomen Rashida Tlaib (D-Detroit) to try and bring down our president,” Lower said in a statement.

Trump carried the 3rd District in 2016 by 9 points, while Amash, who didn’t face a primary challenger the last two election cycles, won a fifth term in November by 11 points. 

Last year, Amash had the second-lowest score among Republicans when it came to supporting Trump in House votes, backing the president’s stated position just 63 percent of the time, according to a CQ Roll Call analysis. North Carolina Rep. Walter B. Jones, who died in February, was the only Republican to score lower. 

Trump took schoolyard swipes at Amash on Sunday, calling him both a “total lightweight” and a “loser.”

“Never a fan of @justinamash, a total lightweight who opposes me and some of our great Republican ideas and policies just for the sake of getting his name out there through controversy,” the president tweeted.

“Justin is a loser who sadly plays right into our opponents hands!”

Never a fan of @justinamash, a total lightweight who opposes me and some of our great Republican ideas and policies just for the sake of getting his name out there through controversy. If he actually read the biased Mueller Report, “composed” by 18 Angry Dems who hated Trump,….

— Donald J. Trump (@realDonaldTrump) May 19, 2019

House Minority Leader Kevin McCarthy dismissed Amash’s comments about impeaching Trump as the drivel of an attention-seeking Republican whom, McCarthy incorrectly said, “votes more with [Speaker] Nancy Pelosi” than his own party.

“It’s a question whether he’s even in our Republican conference as a whole,” the California Republican said.

Based on a voting analysis by FiscalNote, Amash is the Republican who voted the least often — 69 percent of the time — with McCarthy. But that is far more often than Amash voted with Pelosi, which was 20 percent of the time.

Voting similarity is calculated by adding the number of times two representatives vote the same way (either both for or against a measure) and dividing by the number of times they both cast votes.

Data compiled by FiveThirtyEight.com found Amash voted voted with Trump and House Republicans on 91.7 percent of votes since McCarthy became the chamber’s GOP standard-bearer in January.

But in 2018, when Republicans still controlled the chamber, CQ Roll Call found he was the second most likely Republican to oppose the party position on votes, again behind Jones.

Amash voted “present” on a Democratic measures to oppose Trump’s ban on transgender people entering the military and to end U.S. support of Saudi Arabia in its military campaign in Yemen. He bucked the party again in February and March opposing Trump’s emergency declaration for border wall funding.