Did Justin Amash leave the GOP, or did the GOP leave him?

Justin Amash has completed his very public breakup with the Republican Party.

The Michigan Congress member announced he was exiting the GOP in an op-ed in the Washington Post published on Thursday, the Fourth of July. In it, he criticized hyperpartisanship in politics and warned that Congress is reaching a point where it becomes “little more than a formality to legitimize outcomes dictated by the president, the speaker of the House and the Senate majority leader.” Amash wrote that modern politics is “trapped in a partisan death spiral,” but there’s a way out of it: following his lead.

“Today, I am declaring my independence and leaving the Republican Party,” he wrote. “No matter your circumstance, I’m asking you to join me in rejecting the partisan loyalties and rhetoric that divide and dehumanize us.”

Amash, 39, is a conservative libertarian who’s demonstrated an independent streak since he first landed in Congress in 2011 amid the Tea Party wave. That he has become dissatisfied with the state of affairs on Capitol Hill and within the Republican Party is no secret. He has been a vocal critic of President Donald Trump and has often found himself at odds with many of his Republican colleagues.

In May, Amash became the first — and, to date, only — Republican in Congress to say that the president’s conduct is impeachable. In a series of tweets, he also said that Attorney General William Barr had knowingly misled the public on the conclusions of special counsel Robert Mueller’s report and criticized other members of Congress for their lack of action. Amash slammed most of his colleagues for not even reading the entire 448-page report — which he did.

“Mueller’s report reveals that President Trump engaged in specific actions and a pattern of behavior that meet the threshold for impeachment,” he wrote.

Weeks later, Amash left the ultraconservative House Freedom Caucus, of which he was a founding member. He told CNN at the time he didn’t want to be a “distraction.” Prior to that, the Freedom Caucus had already unanimously voted to condemn Amash for criticizing the president.

As for Trump, he’s not shedding any tears over Amash’s exit. In a tweet on Thursday, he called the decision “great news” for the GOP.

Amash’s decision to leave the party signals just how frustrated he has become with the ideological state of affairs in the GOP and its relationship to Trump. He argues that it’s not him who’s changed but the party.

In a recent interview with Vox’s Jane Coaston, Amash said he felt like he was “among the last of the Tea Party,” and while he felt like previously “we were making progress in shifting the dialogue toward limited government and economic freedom and individual liberty,” that’s now changed.

“And over the past few years, it has gone in the other direction, and a lot of the people who once stood with me are no longer there. Some of them got voted out of Congress, and others just don’t emphasize these issues anymore,” he said. “I don’t think it started because of Donald Trump. I believe Donald Trump is the culmination of many years of shift in this direction.”

Amash’s exit also exemplifies how much the Republican Party has capitulated to and become the party of Trump. That’s especially evident in the case of the House Freedom Caucus. As Vox’s Tara Golshan recently explained, the Freedom Caucus “was once a group designed to fight against a certain Republican Party groupthink, to promote small-government and constitutionally conservative ideals, but it is increasingly indistinguishable from Trump.”

Freedom Caucus members Reps. Mark Meadows (R-NC) and Jim Jordan (R-OH) are close to Trump and among his vehement defenders. The group has decided to align itself with the president, much like most of the Republican Party at large, whatever the cost. Per Golshan:

When Republicans controlled the House, the Freedom Caucus, having cultivated Trump’s ear, forced congressional Republican leaders to listen to its demands. They used that power to move the debate on issues like health care and immigration further and further right, often tanking negotiations altogether. But the group has had to accept that Trump wasn’t always aligned with their mission: He’s supported deficit-busting budgets and abandoned cuts to programs like Social Security and Medicare.

What happens with Amash moving forward will be a test for political viability as a conservative who rejects the GOP in the era of Trump. As the New York Times notes, Amash is now the only independent member of the House. There are 235 Democrats and 197 Republicans. He hasn’t said whether he will run for Congress again in 2020, and there has been speculation that he could run for president in 2020 as a libertarian.

As Politico notes, Amash will now probably lose his place on the committees he sits on and will be asked to leave the House Republican Conference; the National Republican Congressional Committee (NRCC) probably won’t back him in a congressional primary because he’s no longer a Republican. Not to mention that the Trump camp will throw its weight behind a primary challenger.

Amash seems determined to do it his way, whatever that means for his political future.

“My oath is to support and defend the Constitution, and that’s what I do. I didn’t run on an oath to support and defend a particular person,” Amash told Coaston. “If some candidate wants to do that, to claim that their oath is to Donald Trump, be my guest. I don’t think that flies as something that will be successful in the campaign in my district. I am who I am, and I wouldn’t want to do this job if I had to be something I’m not.”