Representative Paul Mitchell of Michigan, a two-term Republican who voted for President Trump this year, announced on Monday that he would immediately sever his ties with the Republican Party over its refusal to accept the president’s election defeat.
In a letter to top G.O.P. officials, Mr. Mitchell warned that elected Republicans could help Mr. Trump do “long-term harm to our democracy” by continuing to accommodate and amplify baseless claims of widespread voter fraud. He said he would become a political independent, though he already planned to retire from Congress at the end of this year.
“If is unacceptable for political candidates to treat our election system as though we are a third-world nation and incite distrust of something so basic as the sanctity of our vote,” he wrote just after his state cast its 16 electoral votes for Mr. Biden on Monday. He also decried Republican attacks on the Supreme Court, which on Friday rejected an audacious lawsuit from Texas seeking to overturn the results in key battlegrounds, including Michigan.
One of the wealthiest members of Congress, Mr. Mitchell was first elected in 2016. He has served as a member of Republican leadership, and by his own account voted in favor of the Trump administration’s policies 95 percent of the time
But he has emerged in the weeks since Election Day as one of Mr. Trump’s biggest critics, especially as the president’s lawyers and his allies have made Michigan a leading focus of their attempts to overturn the will of the voters.
Though other Republicans, like Senator Mitt Romney of Utah, have chastised the president and his enablers, Mr. Mitchell is the first elected member of Congress to leave the party over the issue since the election. His fellow Michigan Republican, Representative Justin Amash, left the party last year over concerns about Mr. Trump.
In his letter on Monday, Mr. Mitchell said he supported the right of any candidate to request recounts or challenge results in court. But Mr. Trump and his legal team, he said, had “failed to provide evidence of fraud or administrative failure on a scale large enough to impact the outcome of the election.”
“If Republican leaders collectively sit back and tolerate unfounded conspiracy theories and ‘stop the steal’ rallies without speaking out for our electoral process, which the Department of Homeland Security said was ‘the most secure in American history,’ our nation will be damaged,” Mr. Mitchell wrote, addressing his remarks to Ronna McDaniel, the chairwoman of the Republican National Committee, and Representative Kevin McCarthy, the House Republican leader.