A group of congressional Republicans led by Senator Ted Cruz of Texas objected early Wednesday afternoon to President-elect Joseph R. Biden Jr.’s Electoral College win in Arizona, lodging the first of several extraordinary challenges to its outcome and forcing a two-hour debate in the House and Senate over President Trump’s reckless election fraud claims.
“I rise for myself and 60 of my colleges to object to the count of the electoral ballots from Arizona,” said Representative Paul Gosar, Republican of Arizona. His objection was met with widespread applause by Republicans gathered on the floor of the House of Representatives for the joint session.
Bipartisan majorities in each chamber were prepared to turn back that challenge and others and formalize Mr. Biden’s victory. But the marathon session promised to be a volatile final act of the Trump presidency, with Mr. Trump — unwilling to cede the limelight or his fantasy of victory — transforming a moment of Democratic triumph into a day of defiance by summoning supporters to his backyard for an airing of grievances.
By using the proceeding as a forum for trying to subvert a democratic election, Mr. Trump and his allies are going where no party has since the Reconstruction era of the 19th century, when Congress bargained over the presidency. The effort had already badly divided the Republican Party, forcing lawmakers to go on the record either siding with the president or upholding the results of a democratic election.
The objection to Arizona was the first of at least three expected during Wednesday’s session. Republicans were also eyeing Georgia and Pennsylvania, battleground states Mr. Biden won, for likely objections.
Lawmakers anticipated possible objections for up to three additional states — Michigan, Nevada and Wisconsin — although it was not clear whether they would draw the requisite backing from a member of both the House and the Senate to be considered.
Mr. Cruz, a possible 2024 presidential contender, and his allies in the Senate has said he is merely trying to draw attention to the need for an electoral commission to audit the results. But by objecting, he joined ranks with a group of dozens of House Republicans backing Mr. Trump’s attempt to toss out the will of the voters to deliver him a second term in office.
Even before it began, the session was already driving sharp wedges into the Republican Party that threatened to do lasting damage to its cohesion, as lawmakers decided to cast their lot with Mr. Trump or the Constitution. Top party leaders in the House and Senate appeared to be headed for a high-profile split. And while only a dozen or so senators were expected to vote to reject the outcome in key states, as many as 70 percent of House Republicans could join the effort, stoking the dangerous belief of tens of millions of voters that Mr. Biden was elected illegitimately.
Despite a remarkable pressure campaign by Mr. Trump to unilaterally throw out states that supported Mr. Biden, Vice President Mike Pence, who was presiding as the president of the Senate, said just before the session began that he did not believe doing so was constitutional and would exercise his duties as his predecessors had. The outcome, after for years of loyal support for the president, risked his political standing in a party Mr. Trump still dominates.
“It is my considered judgment that my oath to support and defend the Constitution constrains me from claiming unilateral authority to determine which electoral votes should be counted and which should not,” he wrote in a letter.
Congress’s counting process began at 1 p.m. and the session had already accepted results from Alabama and Alaska before the objection to Arizona was lodged. A member of the House and Senate must agree for any objection to have force.