Rep. Justin Amash, the only Republican in Congress to have accused President Donald Trump of impeachable acts, said Thursday he is leaving the Republican Party and becoming an independent, bemoaning that “modern politics is trapped in a partisan death spiral, but there is an escape.”

Rep. Justin Amash, R-Mich., is the only Republican in the House to call for President Donald Trump’s impeachment. Associated Press/J. Scott Applewhite

In an op-ed in The Washington Post, the Michigan congressman described himself as a lifelong Republican who has grown disenchanted with party politics and frightened by a two-party system that has “evolved into an existential threat to American principles and institutions.”

Citing the warnings of George Washington in his farewell address, Amash said Americans “have allowed government officials, under assertions of expediency and party unity, to ignore the most basic tenets of our constitutional order: separation of powers, federalism and the rule of law.”

He maintained that most Americans are not “rigidly partisan” and the country can do better than the two-party system.

“No matter your circumstance, I’m asking you to join me in rejecting the partisan loyalties and rhetoric that divide and dehumanize us,” Amash wrote, declaring his party affiliation as independent on the nation’s Independence Day.

Amash, who was elected in the tea party wave of 2010, embraced libertarian principles and repeatedly broke with his party on major issues and even the mundane before he challenged the president.

Amash does not mention Trump by name in the op-ed, but his party switch comes weeks after he posted a series of tweets arguing that former special counsel Robert Mueller III documented “impeachable conduct” in his report on Trump’s campaign and administration and Russian interference in the 2016 election. In subsequent public statements, he challenged his colleagues of both parties to take action.

Some 80 House Democrats and several 2020 presidential candidates have called for launching impeachment proceedings against Trump, a step House Speaker Nancy Pelosi, D-Calif., has resisted. Amash is the only Republican.

His stand has drawn the wrath of Trump, who called him “a loser for a long time,” widespread criticism from other Republicans, and a challenger in next year’s election. Amash, 39, who is serving his fourth term, has not announced whether he will run again. He has acknowledged considering instead running for president as a member of the Libertarian Party.

Michigan state Rep. Jim Lower, a Republican, announced his bid for the House seat, describing himself as “a Pro-Trump, Pro-Life, Pro-Jobs, Pro-2nd Amendment, Pro-Family Values Republican.”

Last month, Donald Trump Jr., the president’s eldest son, indicated that he planned to campaign for Lower.

“See you soon Justin,” Trump Jr. said in a tweet. “I hear Michigan is beautiful during primary season.” Attached to his tweet were poll results showing Amash trailing Lower in Michigan’s 3rd Congressional District.

Past supporters of Amash also turned on him in the aftermath of his impeachment comments.

The leader of the Club for Growth, a conservative group that has staunchly backed Amash since his first congressional run in 2010, and whose spending helped him overcome a 2014 primary challenge, criticized the congressman’s comments.

The congressman has been steadfast in defending his position. Facing voters at a town hall in Grand Rapids several weeks ago, Amash said Congress “has a duty to keep the president in check.”

“I’d do it whether it was a Republican president or a Democratic president,” he said. “It doesn’t matter. You elected me to represent all of you.”

House Minority Leader Kevin McCarthy, R-Calif., has dismissed Amash as an outlier among Republicans, citing a number of instances in which the congressman voted with Democrats.

“Justin Amash can determine his own future. But I think, on a philosophical basis, he’s probably in a different place than the majority of all of us,” McCarthy said last month.

Amash also left the conservative House Freedom Caucus, a group he helped found four years ago.

It was unclear whether the congressman would caucus with Democrats. The only other independents in Congress – Bernie Sanders of Vermont and Angus King of Maine – caucus with Democrats in the Senate.

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