Earlier this month, Justin Amash, the libertarian representative of Michigan’s Third congressional district, announced that he was leaving the Republican Party, his political home of the last ten years. In an article published July 4 in The Washington Post—Independence Day, get it?—Amash framed his decision as a classic pox-on-both-houses jeremiad, with the headline declaring: “Our politics is in a partisan death spiral. That’s why I’m leaving the GOP.” But there were enough clues sprinkled throughout to gesture at Amash’s real motivation: that he had worn out his welcome in a party that had long distrusted him and has now been almost wholly captured by Donald Trump.

Quoting George Washington, Amash wrote that blind party loyalty had opened “the door to foreign influence and corruption,” which in turn has come to ensure that the “policy and the will of one country are subjected to the policy and will of another.” If that complaint sounds familiar, it’s because Amash himself had become one of the most forceful voices in the country—and the only Republican in Congress—calling for the president’s impeachment, based on special counsel Robert Mueller’s investigations into Trump’s ties to Russian election-tampering. In his Post op-ed, Amash wrote that devotion to party over principle had undermined “the most basic tenets of our constitutional order: separation of powers, federalism, and the rule of law.”

The divorce had been in the works ever since Amash in May tweeted that Trump’s behavior met the “threshold for impeachment.” Later that month, at a rowdy town hall in Grand Rapids, a tearful woman told him, “You know you have no future in this district as a Republican.” Trump bashed him on Twitter, gleefully noting that Amash was facing primary challenges and calling the congressman “a total loser.” (We’re now up to four announced challengers.) No one in the GOP publicly wanted anything to do with Amash and his battle against Trump, including some of his closest ostensible allies: In June, Amash left the conservative Freedom Caucus that he co-founded in 2015, four years after he stormed into Congress as member of the Obama-hating Tea Party.

Then again, Amash had always been a weird fit inside the increasingly suffocating Republican tent—or any tent for that matter. The son of two immigrants from the Middle East, he has been called a Democrat, “Al Qaeda’s best friend,” and a “Benedict Arnold against the Constitution.” He has ticked off libertarian purists with his wishy-washy position on the border wall, in which he has stressed its sound constitutionality (though here I can speak from experience to testify that libertarian purists are an ornery bunch). He has crossed the GOP enough times to develop a reputation as a gadfly, while his support for an abortion ban after 20 weeks is alienating to many potential Democratic allies. And yet he has been a far more consistent advocate for civil liberties than many on the left, particularly as it relates to surveillance. Most recently, Amash’s bipartisan amendment to curb warrantless surveillance failed in the House, thanks in part to the many Democrats who are unwilling to spend any political capital to make sure Americans are not spied on by their own government.

Amash had always been a weird fit inside the increasingly suffocating Republican tent.

Amash has never pretended to be a party guy. “I’m not here to represent a particular political party,” he told HuffPost in 2016. “I’m here to represent all of my constituents and to follow the Constitution.” His independent streak has recently made him something of a darling among liberals, who have howled at the Democratic congressional leadership’s refusal to bring impeachment proceedings against Trump. But his hard-line position on abortion makes him a lost cause for the left, and he is now the only independent lawmaker in the entire House. The question is where politicians like Amash fit in Trump’s America—and whether his particular brand of libertarianism has a future now that it’s been rather decisively decoupled from the Republican Party.