WASHINGTON, D.C. – Michigan Congressman Justin Amash, who has publicly argued that President Donald Trump engaged in impeachable conduct, announced he is quitting the Republican Party.

Amash, a Republican from Cascade Township who represents Michigan’s 3rd Congressional District, declared his independence from the GOP in a Washington Post op-ed on Thursday, July 4.

“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. I’m asking you to believe that we can do better than this two-party system — and to work toward it. If we continue to take America for granted, we will lose it.”

Amash, who was the only Republican House member to support impeachment proceedings, said he must leave behind America’s two-party system, which he feels “has evolved into an existential threat to American principles and institutions.”

He wrote that although he grew up supporting the Republican Party, which he believed stood for limited government, economic freedom and individual liberty, he has since become “disenchanted” with party politics.

“The two-party system has evolved into an existential threat to American principles and institutions,” he wrote. “...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. The result has been the consolidation of political power and the near disintegration of representative democracy.”

He called upon Americans to stand against the two-party system for the sake of the country’s political future.

“We owe it to future generations to stand up for our constitutional republic so that Americans may continue to live free for centuries to come,” he wrote. “Preserving liberty means telling the Republican Party and the Democratic Party that we’ll no longer let them play their partisan game at our expense.”

Trump fired back at Amash’s calls for impeachment in a series of tweets, blasting the congressman for his remarks on special counsel Robert Mueller’s report.

“Never a fan of (Amash), a total lightweight who opposes me and some of our great Republican ideas and policies just for the sake of getting his name out there through controversy,” Trump tweeted in May.

The Libertarian Party has called on Amash to mount a third-party presidential run, although he has not yet said if he will run as a third-party candidate.

Four candidates have jumped into the race to represent Michigan’s 3rd District in Congress since Amash’s calls for impeachment proceedings in May.

The candidates seeking the Republican nomination are: Peter Meijer, the grandson of late retail magnate Fred Meijer, state Rep. Lynn Afendoulis, R-Grand Rapids Township, state Rep. Jim Lower, R-Greenville, and Tom Norton, a former Sand Lake Village Trustee.