There is growing buzz that Rep. Justin Amash (R-Mich.) will leave the Republican Party to mount a challenge against President Trump as the Libertarian Party's presidential candidate.

Amash, a former attorney who was first elected to Congress during the 2010 Tea Party wave, has thrust himself into the spotlight by becoming the first Republican in the House to support impeachment proceedings for Trump based on special counsel Robert Mueller's findings.

Trump and his allies swiftly fired back, casting Amash as an irrelevant political opportunist who has steadfastly refused to back the GOP agenda in Congress.

But Amash's remarks energized Libertarians and united the "Never Trump" Republicans, who have been unable to recruit a candidate of their own to take on the president in 2020.

In interviews this year, Amash has toyed with the idea of abandoning the Republican Party to run for president as a Libertarian. That could have major implications for Amash's home state of Michigan, which Trump carried by fewer than 11,000 votes in 2016.

There's a full-scale effort underway to convince Amash to take the plunge.

"There are a lot of Libertarian Party members actively encouraging Rep. Amash to switch parties and seek the Libertarian nomination," said Nicholas Sarwark, the chairman of the Libertarian National Committee. "This is probably the most organized recruitment effort I've seen going back to 2012 when people were trying to recruit [former Texas Rep.] Ron Paul."

Trump and his allies have mobilized quickly to shut Amash down.

The president called Amash a "total lightweight" over Twitter, saying he opposes "some of our great Republican ideas and policies just for the sake of getting his name out there."

"Justin is a loser who sadly plays right into our opponents' hands," Trump said.

House Minority Leader Kevin McCarthy (R-Calif.) called Amash's remarks "disturbing" and questioned "whether he's even in our Republican conference."

"He never supported the president, and I think he's just looking for attention," McCarthy said on Fox News's "Sunday Morning Futures.

Amash, a 39-year-old of Palestinian and Syrian descent, has expressed frustration with Republicans, accusing the party of abandoning its principles to accommodate Trump.

He has repeatedly bucked the president and his allies in Congress, co-sponsoring legislation to block Trump's emergency declaration at the border.

And Amash has vented about the "two-party duopoly" while leaving the door open to running as a Libertarian.

In a January interview with the Libertarian publication Reason, Amash was asked what the ideal Libertarian presidential candidate would look like.

"He wears Air Jordans," said Amash, who was wearing the Nike sneakers.

If he were to switch parties, Amash would be the first-ever member of the Libertarian Party in Congress. Libertarians will nominate their presidential candidate at the party convention next May in Austin, Texas.

Former New Mexico Gov. Gary Johnson has been the Libertarian Party's presidential nominee the past two cycles.

Johnson's 2016 campaign was hamstrung by his own gaffes and panned by Washington insiders, but he still managed to post the best showing by any Libertarian presidential candidate ever, receiving nearly 4.5 million votes, or three times as many as the party's prior best showing.

In his home state of New Mexico, Johnson received 9.3 percent of the vote, raising questions about whether Amash could play spoiler for Trump in his home state of Michigan, which is a lynchpin of the president's reelection hopes.

"I don't think Trump can win Michigan if Amash is running," said Sarwark. "They'd have to take it off the board."

Michigan currently has 14 members in the House, but the state's population is shrinking and it's likely it will lose a seat when new maps are drawn after the 2020 census. Most expect Amash's district to be redrawn in a way that will make it tough for him to win reelection to the House. He drew a Trump-supporting primary challenger on Monday.

"He had a very hard time winning in the last election," said McCarthy. "I wonder, maybe he wants some type of exit strategy."

Trump's allies say they're not sweating it, believing that Amash's appeal will be limited to Libertarian voters. They note that Trump's approval rating among Republicans routinely hits 90 percent in the polls.

"Amash's appeal beyond the libertarian and anti-Trump voter is limited in Michigan and elsewhere and will have limited effect on Trump's ability to win here," said Saul Anuzis, the former chairman of the Michigan Republican Party.

Another GOP operative told The Hill that Amash's presence on the ballot may hurt Trump in Michigan but could help him in other battleground states, arguing that independent candidate Howard Schultz is staking out a similar fiscally conservative/socially liberal platform.

Polls show Schultz could play spoiler in the 2020 general election by drawing from the Democratic nominee.

"Every single poll shows that having a third-party candidate in the race hurts the Democrats, and I don't see why Amash would be any different," the GOP source said.

William Weld, the former Republican governor of Massachusetts, has launched his own long-shot primary challenge against Trump.

The "Never Trump" Republicans, led by former Weekly Standard editor Bill Kristol, have been cool on Weld's challenge, which has failed to gain much traction. Weld ran on the ticket with Johnson in 2016 as the Libertarian Party's vice presidential candidate.

But there's no guarantee that Kristol and his allies, who have historically been hostile to the Libertarian right, would back Amash's candidacy.

In a tweet, Kristol praised Amash for standing up to Trump, while noting that he doesn't normally agree with him.

"I say this as someone at odds with Amash on lots of issues important to me and I think to him - all honor to Justin Amash, who has done so much today to set an example of constitutional responsibility and mature, civic discourse," Kristol tweeted.

David French, the National Review writer whom Kristol recruited to challenge Trump in 2016, said he'd back Amash if he ran as a Libertarian against Trump.

Still, there's still a long way to go for Amash to leave an imprint on the 2020 race.

Most presidential cycles begin with optimism that an insurgent third-party challenger can make noise in the race. The challengers usually fall into the background without making much of an impact.

"Anti-Trumpers will find a number of places to go, whether it's a protest vote for one candidate or another," said Anuzis. "The question is, will they be able to concentrate their votes where it counts to make a difference? Most doubt that."