Forty-five Senate Republicans backed a failed effort on Tuesday to halt former president Donald Trump's impeachment trial in a show of party unity that some cited as a clear sign he will not be convicted of inciting insurrection at the Capitol.
Republican Senator Rand Paul made a motion on the Senate floor that would have required the chamber to vote on whether Mr Trump's coming trial is a breach of the US constitution.
The Democratic-led Senate blocked the motion in a 55-45 vote. But only five Republican legislators joined Democrats to reject the move, far short of the 17 Republicans who would need to vote to convict Mr Trump on an impeachment charge over the alleged incitement of the January 6 Capitol riot that left five people dead.
"It's one of the few times in Washington where a loss is actually a victory," Mr Paul said. "Forty-five votes means the impeachment trial is dead on arrival."
But some Republican senators who backed Mr Paul's motion said their vote on Tuesday did not indicate how they might come down on Mr Trump's guilt or innocence in a trial scheduled to begin February 9.
"It's a totally different issue as far as I'm concerned," said Rob Portman, a Republican senator.
The vote came after the senators had been sworn in as jurors for the impeachment trial.
Mr Paul and other Republicans contend that the proceedings are unconstitutional because Mr Trump left office last Wednesday and the trial will be overseen by Patrick Leahy, a Democratic senator, instead of by US Chief Justice John Roberts.
Democratic Senate Majority Leader Chuck Schumer, who moved to thwart Mr Paul's motion, dismissed the Republican constitutional claim as "flat-out wrong" and said it would provide "a constitutional get-out-of-jail-free card" for presidents guilty of misconduct.
There is a debate among scholars over whether the Senate can hold a trial for Mr Trump now that he has left office. Many experts have said "late impeachment" is constitutional, arguing that presidents who engage in misconduct late in their terms should not be immune from the very process set out in the constitution for holding them accountable.
The constitution makes clear that impeachment proceedings can result in disqualification from holding office in the future, so it is still an active issue for the Senate to resolve, scholars said.
Another Republican senator, Lisa Murkowski, who was critical of Mr Trump, rejected Mr Paul's move.
"My review of it has led me to conclude that it is constitutional, in recognising that impeachment is not solely about removing a president; it is also a matter of political consequence," Ms Murkowski said on Tuesday.
She joined fellow Republicans Mitt Romney, Susan Collins, Ben Sasse and Patrick Toomey in opposing Mr Paul.
Mr Trump is the only president to have been impeached by the House of Representatives twice and the first to face a trial after leaving power, with the possibility of being disqualified from future public office if convicted by two thirds of the Senate.
He was acquitted by the formerly Republican-controlled Senate last February on charges of abuse of power and obstruction of Congress arising from his request that Ukraine investigate Democratic rival Joe Biden and his son.
The House approved a single article of impeachment – the equivalent of an indictment in a criminal trial – on January 13, accusing him of inciting an insurrection with an incendiary speech to supporters before they stormed the Capitol. A police officer and four others died in the melee.
But reaching the two-thirds threshold required for conviction will be a steep climb. Mr Trump remains a powerful force among Republicans and his supporters have vowed to mount election challenges to legislators in the party who support conviction.
Some Republicans criticised Mr Trump's unsubstantiated claims of voting fraud and his failed efforts to overturn Mr Biden's November 3 election victory. But no Senate Republicans have said definitively that they plan to vote to convict him.
Although the constitution calls on the chief justice to preside over presidential impeachment trials, a senator presides when the impeached is not the current president, a Senate source said. First elected to the chamber in 1974, Mr Leahy, 80, is the most senior Democrat in the chamber and holds the title of Senate president pro tempore.
The nine House Democrats who will serve as prosecutors set the trial in motion on Monday by delivering the article of impeachment to the Senate.