At the White House, Mr. Trump struck a defiant tone, insisting that he would remain a potent force in American politics as aides and allies abandoned him and his post-presidential prospects turned increasingly bleak. Behind closed doors, he made clear that he would not resign and expressed regret about releasing a video on Thursday committing to a peaceful transition of power and condemning the violence at the Capitol that he had egged on a day before…

Even Senator Mitch McConnell, the majority leader and one of Mr. Trump’s most influential allies for the past four years, told confidants he was done with Donald Trump. Mr. McConnell did not directly weigh on a possible impeachment case, but he circulated a memo to senators making clear that under the Senate’s current rules, no trial could effectively be convened before Jan. 20, after Mr. Trump leaves office and Mr. Biden is sworn in, unless all 100 senators agreed to allow it sooner…

Democrats agreed it was logistically possible to vote on articles of impeachment as soon as next week, but they were weighing how to justify bypassing the usual monthslong deliberative process of collecting documents, witnesses and the president’s defense. Others worried that Mr. Trump’s base would rally more forcefully around him if Democrats pushed forward with impeaching him again, undermining their goal of relegating the 45th president to the ash heap of history.