The push for an unprecedented second impeachment of President Trump took a dramatic bipartisan turn Tuesday, as several senior House Republicans joined the Democratic effort to remove Trump for his role in inciting an angry mob to storm the Capitol last week and the White House braced for more defections.

Rep. Liz Cheney (Wyo.), the third-ranking House Republican, and Rep. John Katko (N.Y.), the top Republican on the House Homeland Security Committee, both publicly held Trump responsible for last Wednesday’s violence. They were later joined by Reps. Adam Kinzinger (R-Ill.), Fred Upton (R-Mich.) and Jaime Herrera Beutler (R-Wash.).

“The president of the United States summoned this mob, assembled the mob, and lit the flame of this attack,” Cheney said in a statement, adding, “There has never been a greater betrayal by a president of the United States of his office and his oath to the Constitution.”

Said Katko, “To allow the president of the United States to incite this attack without consequences is a direct threat to the future of our democracy.”

Kinzinger added, “If these actions . . . are not worthy of impeachment, then what is an impeachable offense?”

A senior administration official said the White House expects at least a dozen Republicans to support impeachment in the likely House vote Wednesday. The White House is rudderless, unwilling or unable to mount any defense other than saying that Trump will already be leaving next week, two administration officials said, speaking on the condition of anonymity to disclose internal dynamics.

Trump, banned from Twitter, for the first time lacks the ability to aim angry tweets at those who oppose him, and White House officials conceded that he has few ways to stem the tide. He has asked Sen. Lindsey O. Graham (S.C.) to urge fellow Republicans to oppose impeachment, an official said. Top House GOP leaders have announced their opposition to impeachment but have not given their members an alternative way to register disapproval of Trump or the assault.

The Democratic-led House ultimately voted on Jan. 12 to officially call on Vice President Pence to remove President Trump by invoking the 25th Amendment. (The Washington Post)

While emotions rose on the House floor, tensions flared outside the chamber. Pelosi on Tuesday imposed new public safety measures on House members, including metal detectors outside the chamber.

That infuriated some Republicans. Several loudly protested to police officers, reporters and Democrats, and others were seen pushing past the metal detectors. Rep. Lauren Boebert (R-Colo.), a freshman gun rights activist, refused to allow Capitol police to inspect her bag.

The Republican statements supporting impeachment — which came after Trump delivered remarks earlier Tuesday expressing no regret for his actions — represented a watershed moment. They signaled high-level GOP concern about the roles of Trump and other party leaders in spreading conspiracy theories about the election, and reflected how much the political landscape has shifted since Trump was acquitted in his first impeachment trial last February.

Meanwhile, Senate Majority Leader Mitch McConnell (R-Ky.) has been telling associates since the attack that Trump probably committed impeachable offenses, as first reported by the New York Times. McConnell, a close adviser said, has not decided how he will vote on impeachment and wants to hear the case first.

McConnell has not returned Trump’s calls in weeks and remains livid with him, and he will not pressure his colleagues to oppose or support convicting the president. “He’s not going to whip the vote,” said the adviser, who spoke on the condition of anonymity to discuss private conversations.

A McConnell spokesman declined to comment.

The White House Counsel’s Office has not drawn up a plan for combating the impeachment effort, an administration official said, and its legislative affairs team is not contacting lawmakers.

Multiple Democratic aides said they expected the full House to vote on impeachment no later than Wednesday night — one week after the shocking Capitol invasion and one week before Trump is set to leave office.

House Speaker Nancy Pelosi (D-Calif.) signaled confidence that the impeachment resolution would pass by naming nine “managers” Tuesday night to act as prosecutors for the Senate trial, led by Rep. Jamie B. Raskin (D-Md.).

House members took a preliminary step toward impeachment Tuesday evening, approving a resolution urging Vice President Pence and the Cabinet to use their powers under the 25th Amendment to remove Trump immediately. In a letter to Pelosi late Tuesday, Pence wrote that such an action would not be “in the best interest of our Nation or consistent with our Constitution.”

The resolution passed anyway, 223 to 205, with Kinzinger the only Republican supporting it. Katko was among those who opted not to support it in light of Pence’s letter, calling it “merely a symbolic gesture.”

Pelosi had indicated that if Pence did not act, she would move immediately to impeach the president.

No House Republicans joined the Democrats in December 2019 when they impeached Trump for urging Ukraine to investigate Joe Biden and his son, but the Capitol attack has shaken the Republican ranks.

The formal debate over sanctioning Trump began Tuesday morning when the House Rules Committee readied the 25th Amendment resolution for the House floor. The mood of the debate went from somber to angry, as lawmakers sparred about Trump’s culpability — and one another’s — for last Wednesday’s events.

“Rushing this resolution to the floor will do nothing to unify or heal the country,” said Rep. Jim Jordan (R-Ohio). “These actions, again, will only continue to divide the nation.”

In response, Rules Committee Chairman Jim McGovern (D-Mass.) accused Jordan and others of having “given oxygen to the president’s conspiracy theories” and said appeals to civility were coming too late.

“We all want healing, but in order to get to healing, we need truth and we need accountability,” McGovern said.

Trump on Tuesday denied responsibility for last week’s riot. “People thought that what I said was totally appropriate,” he said.

At a rally that day, Trump urged his followers to head for the Capitol and “fight much harder” to prevent Biden’s victory from being certified in Congress. “If you don’t fight like hell, you’re not going to have a country anymore,” he said.

On Tuesday, Trump suggested that proceeding with impeachment might spark additional violence: “I think it’s causing tremendous danger to our country, and it’s causing tremendous anger. I want no violence.”

The sole impeachment article charges Trump with “incitement of insurrection,” and several GOP lawmakers were openly mulling whether to support it.

Cheney has not explicitly recruited other Republicans to join her call for impeachment, but she has signaled her disapproval of Trump’s conduct and served as a sounding board for other concerned Republicans. On a Monday conference call, she told colleagues she considered impeachment a “vote of conscience.”

She announced her intention to vote to impeach Trump a day in advance of the vote as an encouragement to wavering members, multiple Republicans said.

Meanwhile, Minority Leader Kevin McCarthy (R-Calif.) and Whip Steve Scalise (R-La.), the two House members who outrank Cheney in the Republican hierarchy, have opposed impeachment, putting them on the other side of the divide over Trump that is beginning to cleave the GOP.

Six moderate Republicans, led by Reps. Brian Fitzpatrick (R-Pa.) and Tom Reed (R-N.Y.), introduced a censure resolution Tuesday accusing Trump of trying to “unlawfully overturn” the election — a measure that many GOP lawmakers privately signaled they would be willing to rally around.

But the top leaders did not openly endorse it, including McCarthy, who acknowledged Trump’s culpability for the riot in a Monday evening conference call with his colleagues. They appear to have calculated that any break with Trump would further upend their party.

The rift is roiling the GOP leadership ranks barely two months after unexpected gains in the November elections had McCarthy predicting he would be claiming the speaker’s gavel after the 2022 midterms.

Now it’s unclear whether he can keep his conference united, while for Cheney, the fallout may be more immediate, since pro-Trump lawmakers demanded her resignation as Republican conference chair within hours after her announcement on impeachment.

“She should not be serving this conference,” said Rep. Andy Biggs (R-Ariz.), chairman of the Trump loyalist House Freedom Caucus.

House members debating Tuesday’s resolution provided something of a preview of Wednesday’s likely debate on impeachment.

Jordan, who promulgated conspiracy theories about election fraud and attended a “Stop the Steal” rally after the election, accused Democrats of a “double standard” since they had raised objections to the electoral votes of Republican presidents, including Trump and George W. Bush.

Democrats noted that in those cases, the losing candidate had long since conceded and many lawmakers who protested made clear that they accepted the election results, while at no point encouraging violence.

Raskin cited liberals’ reaction to Trump’s election, including a massive Women’s March on Washington.

“What did the Democrats do? They put on pink winter hats, marched peacefully with a million people, joined Planned Parenthood, worked with their churches to try to reform America,” Raskin said. “Nobody was out there agitating for a violent armed insurrection against the government.”

Another Democrat, Rep. Ed Perlmutter (Colo.), pleaded with Jordan to acknowledge that the election was not stolen and that Biden had won.

“Yes, he’s going to be president,” Jordan said, but added, “There are serious problems with this election that deserve an investigation.”

The sparring came as Democrats debated how to structure their next steps after impeachment passes the House. The Senate is not scheduled to return to regular business until Jan. 19, a day before Biden’s inauguration, meaning there would be virtually no chance of conducting a Senate trial and ousting Trump from office prematurely.

Senate Minority Leader Charles E. Schumer (D-N.Y.) called on McConnell to join him in invoking a provision that allows the Senate to convene early in cases of emergency, if both party leaders call for it.

“This is a time of emergency,” Schumer said. “We could come back ASAP and vote to convict Donald Trump and get him out of office now, before any further damage is done.”

Asked whether the House could delay transmission of the impeachment resolution, allowing the Senate to confirm at least some of Biden’s Cabinet nominees before plunging into an impeachment trial, Pelosi declined to comment Tuesday.

Democrats have also discussed the potential for “bifurcating” Senate business so that the chamber could, for example, approve nominees in the morning and hold a trial in the afternoon. But there is no modern precedent for doing that, and it would require cooperation from Republicans that they may be unlikely to grant.

Erica Werner contributed to this report.