Michigan Rep. Justin Amash said Thursday that he's leaving the Republican party to become an independent as modern politics remains "trapped in a partisan death spiral."

Penning an op-ed in the Washington Post on the July 4th holiday, Amash described how he had become "disenchanted with party politics" and "frightened by what I see from it."

"The two-party system has evolved into an existential threat to American principles and institutions," Amash wrote.

Amash was the only GOP member of Congress to have come out in favor of impeaching President Donald Trump in light of special counsel Robert Mueller's report on Russian interference in the 2016 election.

Amash said in May that Trump had "engaged in impeachable conduct" regarding obstruction of justice and accused Attorney General William Barr of distorting the report's conclusions.

The stance drew attacks from the president, who called the lawmaker a "loser" who only sought to make headlines.

"Justin is a loser who sadly plays right into our opponents hands!" Trump tweeted.

House Minority Leader Kevin McCarthy, R-Calif., also agreed that Amash made his statement because he "wants to have attention."

Mueller's report explicitly said that the investigation looked into 10 potentially obstructive acts and the evidence did not clear the president. Rather, it said, "while this report does not conclude that the President committed a crime, it also does not exonerate him" and punted that decision to the attorney general. Barr and then-deputy Attorney General Rod Rosenstein ultimately decided not to bring charges against the president.