Far from explaining his position, Mr. McConnell has assumed a sphinx-like silence in public. As late as Tuesday morning, according to the Republicans who had been informed of the talks, his own advisors were not sure how he was going to vote on Mr Paul’s motion. He has refused to explain his vote and told reporters on Wednesday that he wanted to be open as a juror in the upcoming trial.

“Well, the process hasn’t started yet,” he said. “And I intend to participate and listen to the evidence.”

His advisors refused to speculate on his thinking.

Mr. McConnell continues to strive to go beyond Mr. Trump. While his counterpart, California Representative Kevin McCarthy, was scheduled to meet with Mr Trump on Thursday to re-establish his relationship with the former president, the Senate chairman was happy to tell reporters that he had not spoken to Mr Trump since December 15, after Mr. McConnell had congratulated Mr. Biden as President-Elect. He’s told allies he hoped never to speak to Mr. Trump again.

Yet his public silence baffled even some of the most loyal members of his conference.

Senator Kevin Cramer of North Dakota, who last week said Mr. McConnell had told him to vote his conscience on impeachment issues, went over a number of possible explanations for the leader’s vote on Wednesday.

“Perhaps this is one of those voices you can use to reflect your conference, and of course he does very often,” he said of Mr. McConnell. “Our conference has been quite overwhelming in their support.”

The vote clearly confused some Democrats, some of whom wondered if it was even worth it – or the cost to Mr Biden – to spend time on impeachment that was again destined for acquittal. Senators Tim Kaine, Democrat of Virginia and Susan Collins, Republican of Maine, launched a bipartisan criticism of Mr. Trump in lieu of trial and sparked a heated debate on the issue.

“Going through a process in the knowledge that you will receive a maximum of 55 votes does not seem to me to be the right prioritization of our time,” complained Mr. Kaine.