WASHINGTON — Democrats laid the groundwork on Friday for impeaching President Trump a second time, as Speaker Nancy Pelosi of California threatened to bring him up on formal charges if he did not resign “immediately” over his role in inciting a violent mob attack on the Capitol this week.
The threat was part of an all-out effort by furious Democrats, backed by a handful of Republicans, to pressure Mr. Trump to leave office in disgrace after the hourslong siege by his supporters on Wednesday on Capitol Hill. Although he has only 12 days left in the White House, they argued he was a direct danger to the nation.
Ms. Pelosi and other top Democratic leaders continued to press Vice President Mike Pence and the cabinet to invoke the 25th Amendment to wrest power from Mr. Trump, though Mr. Pence was said to be against it. The speaker urged Republican lawmakers to pressure the president to resign immediately. And she took the unusual step of calling Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, to discuss how to limit Mr. Trump’s access to the nation’s nuclear codes and then publicized it.
“If the president does not leave office imminently and willingly, the Congress will proceed with our action,” Ms. Pelosi wrote in a letter to colleagues.
At least one Republican, Senator Lisa Murkowski, Republican of Alaska, followed Ms. Pelosi’s lead and told The Anchorage Daily News that she was considering leaving the Republican Party altogether because of Mr. Trump.
“I want him out,” she said. “He has caused enough damage.”
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.
He said on Twitter on Friday morning that he would not attend President-elect Joseph R. Biden Jr.’s inauguration, the first incumbent in 150 years to skip his successor’s swearing-in. Hours later, Twitter “permanently suspended” his beloved account, which had more than 88 million followers, “due to the risk of further incitement of violence.”
Federal law enforcement officials announced charges against at least 13 people in connection with the storming of the Capitol, including Richard Barnett, 60, of Gravette, Ark., who had posted a picture of himself on social media sitting at Ms. Pelosi’s desk during the mayhem with his feet up on her desk, and a Republican state delegate from West Virginia.
Among enraged Democrats, an expedited impeachment appeared to be the most attractive option to remove Mr. Trump and register their outrage at his role in encouraging what became an insurrection. Roughly 170 of them in the House had signed onto a single article that Representatives David Cicilline of Rhode Island, Ted Lieu of California, Jamie Raskin of Maryland and others intended to introduce on Monday, charging the president with “willfully inciting violence against the government of the United States.”
Democratic senators weighed in with support, and some Republicans appeared newly open to the idea. Senator Ben Sasse of Nebraska indicated he would be amenable to considering articles of impeachment at a trial. A spokesman for Senator Susan Collins of Maine said she was “outraged” by Mr. Trump’s role in the violence, but could not comment on an impeachment case given the possibility she could soon be sitting in the jury.
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.
It was a fitting denouement for a president who, despite years of norm-shattering behavior, has acted largely without consequence throughout his presidency, showing no impulse to change his ways, despite being impeached in Congress, defeated at the ballot box and now belatedly shunned by some members of his own party.
By Friday evening, Ms. Pelosi had not made a final decision on whether to proceed with impeachment and was wary of rushing into such a momentous step. She issued a statement saying she had instructed the House Rules Committee to be ready to move ahead with either an impeachment resolution or legislation creating a nonpartisan panel of experts envisaged in the 25th Amendment to consult with Mr. Pence about the president’s fitness to serve.
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.
Republicans who only days before had led the charge to overturn Mr. Trump’s electoral defeat said impeaching him now would shatter the unity that was called for after the Capitol siege.
“Impeaching the president with just 12 days left in his term will only divide our country more,” said Representative Kevin McCarthy of California, the Republican leader, just a day after he voted twice to overturn Mr. Biden’s legitimate victory in key swing states.
Judd Deere, a White House spokesman, issued a nearly identical statement.
Democrats, too, were concerned about plunging Washington into a divisive, time-consuming and politically fraught drama that would overshadow and constrain Mr. Biden’s agenda and stomp on his attempt to unify the country.
During an appearance in Wilmington, Del., Mr. Biden declined to directly weigh in on plans to impeach Mr. Trump saying, “What the Congress decides to do is for them to decide.” But he made clear his energies were being spent elsewhere.
“If we were six months out, we should be moving everything to get him out of office — impeaching him again, trying to invoke the 25th Amendment, whatever it took to get him out of office,” Mr. Biden said. “But I am focused now on us taking control as president and vice president on the 20th and get our agenda moving as quickly as we can.”
Mr. Trump had told advisers in the days before the march that he wanted to join his supporters in going to the Capitol, but White House officials said no, according to people briefed on the discussions. The president had also expressed interest beforehand in calling in the National Guard to hold off anti-Trump counterprotesters who might show up, the people said, only to turn around and resist calls for bringing those troops in after the rioting by his loyalists broke out.
On Friday, Mr. Biden had harsh criticism for Senators Josh Hawley of Missouri and Ted Cruz of Texas, Republicans who had lodged objections to his Electoral College victory on Wednesday amid the mayhem at the Capitol. As some leading Senate Democrats called on them to resign, Mr. Biden said the pair had perpetuated the “big lie” that his election had been fraudulent, comparing it to the work of the Nazi propaganda minister Joseph Goebbels.
The recriminations played out on a day when workers in the Capitol were literally repairing the damage that had been done two days before, when a mob of supporters, egged on by Mr. Trump, stormed the Capitol as lawmakers were formalizing Mr. Biden’s electoral victory. Lawmakers mourned the death of a Capitol Police officer who succumbed to injuries sustained while defending the building.
From the same office ransacked by the mob, Ms. Pelosi was working furiously on Friday to try to contain Mr. Trump. She urged Republicans to follow the model of Watergate, when members of their party prevailed upon President Richard M. Nixon to resign and avoid the ignominy of an impeachment.
She also said she had spoken with General Milley about “preventing an unstable president from initiating military hostilities or accessing the launch codes.”
A spokesman for General Milley, Col. Dave Butler, confirmed that the two had spoken and said the general had “answered her questions regarding the process of nuclear command authority.” But some Defense Department officials have privately expressed anger that political leaders seemed to be trying to get the Pentagon to do the work of Congress and cabinet secretaries, who have legal options to remove a president.
While military officials can refuse to carry out orders they view as illegal, they cannot proactively remove the president from the chain of command. That would be a military coup, these officials said.
Ms. Pelosi elaborated on her thinking in a private call with House Democrats, indicating she was particularly concerned about Mr. Trump’s behavior while he remained commander in chief of the armed forces, with the authority to order nuclear strikes.
“He’s unhinged,” Ms. Pelosi, according to Democrats familiar with her remarks. “We aren’t talking about anything besides an unhinged person.”
She added: “We can’t move on. If we think we can move on then we are failing the American people.”
Democrats appeared to be largely united after the call, which lasted more than three hours, that the chamber needed to send a strong message to Americans and the world that Mr. Trump’s rhetoric and the violence that resulted from it would not go unanswered.
Ms. Pelosi had asked one of her most trusted deputies who prosecuted Democrats’ first impeachment case against Mr. Trump, Representative Adam B. Schiff of California, to give a frank assessment of the potential drawbacks of impeachment during the session.
Mr. Schiff did so, but later issued a statement saying, “Congress should act to begin impeachment proceedings as the only instrument wholly within our power to remove a president who has so manifestly and repeatedly violated the Constitution and put our nation at grave risk.”
At least one Democrat, Representative Kurt Schrader, a centrist from Oregon, argued against impeachment, likening the move to an “old-fashioned lynching” of Mr. Trump, and arguing it would turn the president into a martyr. He later apologized for the analogy.
A bipartisan group of centrist senators, including several who helped draft a stimulus compromise last month, discussed the possibility of drafting a formal censure resolution against Mr. Trump. But it was unclear if a meaningful attempt to build support for censure would get off the ground, especially with Democrats pushing for a stiffer punishment.
After years of deference to the president, leading Republicans in Congress made no effort to defend him, and some offered stinging rebukes. At least a few appeared open to the possibility of impeachment, which if successful could also disqualify Mr. Trump from holding political office in the future.
Mr. Sasse said he would “definitely consider whatever articles they might move because I believe the president has disregarded his oath of office.”
“He swore an oath to the American people to preserve, protect and defend the Constitution — he acted against that,” Mr. Sasse said on CBS. “What he did was wicked.”
Senior Republican aides predicted other senators could adopt a similar posture, so deep was their fury at Mr. Trump. But they held back publicly, waiting to better understand a volatile and rapidly evolving situation.
If the House did impeach, and the Senate put Mr. Trump on trial, 17 Republicans or more would most likely have to join Democrats to win a conviction. That was a politically perilous and unlikely decision given his continued hold on millions of the party’s voters.
At the same time Republicans in Washington were chastising Mr. Trump, the Republican National Committee re-elected Ronna McDaniel, a Trump ally and his handpicked candidate, as its chairwoman for another term, and Tommy Hicks Jr., a close friend of Donald Trump Jr.’s, as the co-chairman.
Political risks for Republicans breaking ranks were also on vivid display on Friday at National Airport near Washington, where several dozen jeering supporters of Mr. Trump accosted Senator Lindsey Graham of South Carolina, angrily denouncing the Republican as a “traitor” and a “liar” for voting to formalize Mr. Biden’s victory.
“It’s going to be like this forever, wherever you go, for the rest of your life,” one woman taunted to Mr. Graham, who had been one of Mr. Trump’s leading Senate allies and had initially humored his baseless claims of widespread election fraud.
Nicholas Fandos and Luke Broadwater reported from Washington, and Maggie Haberman from New York. Reporting was contributed by Peter Baker, Helene Cooper, Emily Cochrane and Catie Edmondson from Washington.