Rep. Justin Amash (R-MI) over the weekend broke with his fellow Republican colleagues after reading special counsel Robert Mueller’s report on Russian interference in the 2016 election. His conclusions: Attorney General William Barr had badly misconstrued the report’s contents in his representations of the material and President Donald Trump had committed acts that, to his mind, had crossed the “threshold of impeachment.”

Along the way, Amash had harsh words for his colleagues on both sides of the aisle, suggesting that not many of them had “even read Mueller’s report,” and that “their minds” had been “made up based on partisan affiliation — and it showed.”

As if to underscore this, Amash’s fellow Republicans have heaped scorn upon the five-term congressman. And naturally, Trump led the way on his favorite medium, Twitter — referring to Amash as a “loser” and a “lightweight.”

“Justin is a loser that plays right into our opponent’s hands,” the president tweeted Sunday.

In her own remarks, Republican National Committee (RNC) Chairwoman Ronna McDaniel echoed the president, accusing Amash of “parroting the Democrats’ talking points on Russia.”

She continued: “The only people still fixated on the Russia collusion hoax are political foes of President Trump hoping to defeat him in 2020 by any desperate means possible. Voters in Amash’s district strongly support this President, and would rather their Congressman work to support the president’s policies that have brought jobs, increased wages and made life better for Americans.” (While the Cook Political Report found Trump to be popular in Amash’s 3rd District, where he bested Democratic presidential candidate Hillary Clinton by a 52-42% margin, Amash won his own re-election in 2016 by a much larger margin, 59-37%.)

Amash was also rebuked by House Minority Leader Kevin McCarthy (R-CA), who suggested that the Michigan congressman was simply acting out of a desire for self-aggrandizement. “It’s very disturbing,” McCarthy insisted. “This is exactly what you would expect from Justin. He never supported the president. And I think he’s just looking for attention.”

“He votes more with [House Speaker] Nancy Pelosi than he ever votes with me,” McCarthy added.

This drew a response from Amash on Monday: “I think everyone knows he’s lying. That’s typical Kevin.”

Perhaps the unkindest — though hardly unexpected — cut came from the Republicans of the House Freedom Caucus, which Amash was instrumental in founding. On Monday, that body condemned Amash for supporting the president’s impeachment. Rep. Jim Jordan (R-OH) told reporters, “We had a good discussion and every single member, I think now based on who was there and our board meeting was probably over 30 members, every single member disagrees and strongly with the position Justin took.”

Amash’s fellow Republicans can hardly claim to be surprised, however, as the Michigander has been a frequent critic of the president — and has never sought an alliance with the former real estate mogul. Moreover, Amash was the first Republican to call for an independent investigation into Russian interference in the 2016 election — immediately after Trump fired FBI director James Comey in May of 2017.

My staff and I are reviewing legislation to establish an independent commission on Russia. The second paragraph of this letter is bizarre. https://t.co/wXeDtVIQiP

— Justin Amash () May 9, 2017

Amash — along with former Rep. Carlos Curbelo (R-FL) — raised the specter of impeachment back in 2017 as well, telling The Hill’s reporter Cristina Marcos that the allegations raised by Comey in his memos were, if true, impeachable offenses.

Additionally, in February of this year, Amash appeared to be the only Republican interested enough to prepare to question former Trump attorney Michael Cohen with any degree of seriousness.

Amash has long been a gadfly of the GOP establishment, which last tried to unseat him in 2014 in a contentious primary race marked by vitriol and infighting. Among the lowlights was current Trump ally Rep. Devin Nunes (R-CA) referring to Amash — who is Arab American — as “al-Qaeda’s best friend in Congress.” At the end of that primary race, Amash famously broke with polite protocol at his victory speech to heap scorn and insult upon his opponent, Brian Ellis, and his backers. Amash did not draw a serious primary opponent in the two election cycles that followed.

On Monday, Michigan state Rep. Jim Lower (R) announced that he will try to unseat Amash in 2020, citing his call to impeach Trump.