Rep. Justin Amash (R-Mich.), 39, was voted into Congress during the 2010 Tea Party wave. Prior to serving in government, he was an attorney.

In recent times he has been critical of Donald Trump, even going so far as to join Democrats in calling for the president’s impeachment. He is the first Republican Congressmen to do so, and speculation is rising that Amash is planning to challenge Trump during the 2020 election by heading the Libertarian Party ticket.

While Trump and his political allies lambasted Amash, Libertarians and Republicans who dislike Trump — both groups that’ve had trouble finding a politician to rally behind — have taken to him. It also bears mentioning that Michigan, Amash’s home state, was only won by Trump in 2016 by less than 11,000 votes. “I don’t think Trump can win Michigan if Amash is running,” said Libertarian National Committee chairman Nicholas Sarwark. “They’d have to take it off the board.”

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In interviews, Amash has played with the idea of converting over to the Libertarian Party, and has once lamented over the country’s “two-party duopoly.” If Amash were to switch parties, he would become the first Libertarian Congress member.

The Libertarian Party itself would fully welcome him into their roster. “There are a lot of Libertarian Party members actively encouraging Rep. Amash to switch parties and seek the Libertarian nomination,” said Sarwark. “This is probably the most organized recruitment effort I’ve seen going back to 2012 when people were trying to recruit [then-Texas Rep.] Ron Paul.”

Former New Mexico Gov. Gary Johnson was featured on the Libertarian ticket for the last two presidential elections, but his 2016 bid was hurt by numerous blunders. Next May, the Libertarian Party will host a convention in Austin, Texas. Its 2020 presidential contender will be decided then.