House Speaker Nancy Pelosi vowed Sunday to push ahead with impeaching President Trump if he is not removed from office first, adding a powerful voice to a debate that has begun to consume a Democratic Party both eager for impeachment and wary of it.

Her statement virtually assures the House will move forward with impeachment, even as tensions break out among Democrats over how aggressively to push for it. House members have insisted Trump face consequences for inciting last week’s deadly assault on the U.S. Capitol, while President-elect Joe Biden has signaled he does not want the effort to interfere with his agenda.

Both sides are treading carefully, aware that many voters hope Congress will prevent Trump from provoking further violence, but also want Biden to be free to take immediate action on the coronavirus pandemic and a faltering economy. Some Democrats said privately that they are wary of impeachment but unsure how to slow its momentum given intensifying passions against Trump.

Democrats and Republicans weighed in on Jan. 10 about whether impeaching President Trump was warranted days after a pro-Trump mob stormed the U.S. Capitol. (The Washington Post)

The conflict confronts Biden with his first test on what could be an early, incendiary dilemma facing his presidency: how hard to pursue accountability for Trump and those in his orbit.

“There has to be consequences, and that can take various forms,” said Rep. Dean Phillips (D-Minn.). “Clearly impeachment has its own consequences, and we recognize that we don’t want to impact the Biden administration. And we want to ensure that whatever we pursue can be achieved.”

Pelosi (D-Calif.) on Sunday said the House would “proceed with bringing impeachment legislation to the Floor” but announced no firm timeline to do so. Instead she delivered an ultimatum to Vice President Pence: Democrats plan to first pass a resolution calling on Pence and the Cabinet to remove Trump under the provisions of the 25th Amendment before proceeding with impeachment.

“As the days go by, the horror of the ongoing assault on our democracy perpetrated by this President is intensified and so is the immediate need for action,” she said.

In a sign of the Democrats’ struggles with the issue, Rep. James E. Clyburn (D-S.C.), a Biden ally and House leader, proposed Sunday that the House vote this week to impeach but wait a few months to submit the articles of impeachment to the Senate for a trial.

Those comments provoked widespread frustration among Democrats, according to multiple aides and lawmakers, who spoke on the condition of anonymity to air internal discussions, and they worried that Clyburn’s remarks would undermine the party’s case for Trump’s quick removal: that he is an immediate danger to the nation.

But Clyburn’s suggestion was not universally spurned. Another House Democrat, Rep. Jason Crow (Colo.), said in an interview Sunday that the House could delay transmitting the articles long enough to allow the Senate to confirm key national security nominees.

“We are witnessing the birth of a domestic terrorist movement in the United States, and it’s really important that we get Biden inaugurated, that he gets his Cabinet into place . . . as quickly as possible so we can address that threat,” said Crow, who supports a rapid impeachment. “And let’s not forget that we have foreign adversaries that are looking to take advantage of moments of weakness and distraction like we have right now.”

Some Democrats are looking to Biden to take a firm public stance and slam the brakes on impeachment, but top Democrats now see it as increasingly unlikely that the president-elect will go further than his measured warning on Friday that whatever else Congress does, it needs to “hit the ground running” on his agenda when he takes office.

“The train has left the station. I think many are worried about how it gets done, how it’s going to be handled, and how do we make sure it’s not going to divide the country further,” one Democrat said of impeachment. “It’s on a track that, while people have reservations, nobody knows how to stop it.”

On Monday morning, various House members plan to introduce responses to Wednesday’s assault on the Capitol and Trump’s role in encouraging it. Pelosi said Democrats would seek unanimous consent at a brief pro forma session to pass the 25th Amendment measure. Republicans are likely to block that move, however, forcing a floor vote Tuesday.

The earliest action on impeachment could come Tuesday in the House Rules Committee, which would meet to prepare legislation for the House floor; actual votes on impeachment or other items can occur no sooner than Wednesday — a week before Biden’s inauguration.

As of Sunday afternoon, a draft impeachment resolution had garnered 210 co-sponsors in the House, according to Rep. David N. Cicilline (D-R.I.), one of its authors.

Pelosi and other Democratic leaders are increasingly determined to hold Trump immediately accountable and force his Republican defenders to choose whether to stand by him — a stance that has been reinforced by members’ personal anger at the breach of the Capitol, as well as the fumbling, often-equivocal GOP response. Several said the Republican calls dismissing impeachment as too divisive have only further infuriated Democrats.

“Republicans need to be put on the record,” Pelosi said on a Thursday call with her leadership team, according to two people familiar with her remarks.

Phillips said it was clear impeachment would move forward unless Republicans embraced an alternative: “It is now Sunday evening, and we’re still awaiting any proposition from the GOP to hold him to account,” he said. “Many of my colleagues on the other side of the aisle are talking about unity. … If we want unity within the Congress, I invite a proposition from the GOP to fulfill those conservative principles of accountability and consequence.”

Among those joining the effort Sunday was Rep. Stephanie Murphy (D-Fla.), co-chair of the moderate Blue Dog Coalition, who said in a tweet that Congress has a “constitutional and moral obligation” to hold the president accountable “for inciting violence and insurrection.”

Another prominent Blue Dog — Rep. Kurt Schrader (D-Ore.), who raised concerns about a rapid impeachment on a Friday teleconference of House Democrats — backed the effort late Saturday. “While I have pushed other remedies for his criminal conduct, impeachment is the tool before us and warranted for his seditious acts,” he tweeted.

House Republicans are planning their own conference call on Monday to discuss their approach.

Democrats must act quickly, because Trump is scheduled to leave office on Jan. 20 in any case. And the rage of many Democrats is colliding with Biden’s urgent need to set up an administration that will immediately face multiple crises — as well the need to repair a government the Biden team sees as badly damaged and demoralized.

A Senate engulfed in an impeachment trial would struggle to do anything else, and Biden has already voiced frustration that senators have not moved faster to confirm his Cabinet picks.

“There is an appetite to better understand where President-elect Biden’s head is at relative to what he believes is in the best interest,” Phillips said, acknowledging that Biden doing so publicly “presents complications.”

The dilemma led to a flurry of alternative proposals Sunday as lawmakers looked for a way to navigate the cross-pressures.

Clyburn said his idea of waiting until after the Biden administration’s first 100 days to send articles of impeachment to the Senate would allow the new president install key members of his team. “Let’s do the people’s work and let’s vote to impeach this president, and then we’ll decide later — or the Senate will decide later — what to do with that,” Clyburn said.

Others said Congress should censure Trump instead of impeaching him, an action that could be taken quickly and possibly attract broader support.

Del. Eleanor Holmes Norton (D), the District of Columbia’s nonvoting representative in the House, said she plans to introduce such a measure Monday, describing it as “the only way to send a bipartisan, bicameral message without delay to the country and the world that the United States is a nation of laws.”

Rep. Adam Kinzinger (R-Ill.), a frequent Trump critic, also suggested he would back a censure motion.

But other Democrats have expressed concern that if the House and Senate do not act quickly, Trump and his supporters will be emboldened to continue working to overturn Biden’s election, and that the country may be wracked by further threats to the safety of lawmakers, officials and the democratic system.

On Sunday, a handful of high-profile Republicans, including Sen. Patrick J. Toomey (Pa.) and former New Jersey governor Chris Christie, joined the calls for Trump’s removal, potentially making it even harder for any Democratic leader to oppose impeachment.

Pelosi told CBS News’s “60 Minutes” that one reason to impeach Trump would be to prevent him from running again in 2024. “There’s strong support in the Congress for impeaching the president a second time,” she said in the interview, which was taped Friday and aired Sunday.

Rep. Ted Lieu (D-Calif.), responding to the argument from some Republicans that impeachment would be a “bad start” for Biden as he seeks to unify the country behind an ambitious agenda, said in a tweet that the country “cannot heal until we first get justice.”

Rep. Alexandria Ocasio-Cortez (D-N.Y.), a second-term congresswoman who is among the leading voices of the party’s liberal wing, suggested Democrats should pursue an “all-of-the-above” approach that includes various avenues for ousting the president.

She rejected the idea that removing Trump should take a back seat to Biden’s plans, suggesting Biden’s own safety may be at stake.

“With profound respect, I believe that the president’s safety and the safety of the United States Congress and the security of our country takes precedent over the timing of nominations and the timing of potential confirmations,” Ocasio-Cortez said on ABC News’s “This Week.” “This is an immediate danger right now.”

Some Democrats are pushing for the invocation of the 25th Amendment, which provides for the removal of an unfit president, as a way to resolve the issue quickly without involving Congress. Pelosi said she favors that “because it gets rid of him; he’s out of office.”

But that would require Pence and a majority of the president’s Cabinet to support removing Trump, an unlikely scenario. Some Democrats also cite the 14th Amendment, which prevents individuals from holding office if they have supported insurrection, but that, too, seems remote.

Neither Biden nor Trump spoke publicly Sunday, and the president has been barred from Twitter, his preferred communication channel. White House spokesman Judd Deere said Trump is expected to travel to Alamo, Tex., on Tuesday to mark progress on his border wall.

While Biden did not directly weigh in on impeachment, he reiterated in a tweet Sunday his theme of looking ahead, saying, “In 10 days, we move forward and rebuild — together.”

That echoed the message of his news conference Friday, when he told reporters he was focused on “getting our agenda moving as quickly as possible” and declined to call on Congress to take any particular action against Trump, saying it was their decision.“There can only be reconciliation with repentance,” Coons said.

“We were duly elected, so I think it’s important that we get on with the business of getting him out of office — and the quickest way that that will happen is us being sworn in on the 20th,” Biden said.

One close Biden ally, Sen. Christopher A. Coons (D-Del.), said on CBS’s “Face the Nation” that the most important thing Republicans can do is stop spreading the falsehood that the 2020 election was stolen and help convince Trump’s supporters that Biden is the duly elected president.

Most Republicans have largely been silent about any consequences for Wednesday’s riot, whether for Trump or the members of Congress who encouraged them. But some on Sunday joined Democrats in calling for Trump to leave office.

Asked on CNN’s “State of the Union” whether Trump should step down, Toomey said, “I think at this point, with just a few days left, it’s the best path forward, the best way to get this person in the rearview mirror for us.”

Speaking on “Fox News Sunday,” Trump’s former chief of staff, Mick Mulvaney, said that of all of the things Trump has done, “I could probably defend almost all of them” until this point. But in the riot’s aftermath, he added, he would “seriously” consider voting to impeach Trump if he were still a House member.

On ABC’s “This Week,” Christie, a former Trump backer, said he would also vote to impeach if he were in Congress. “If inciting to insurrection isn’t [an impeachable offense], then I don’t really know what is,” Christie said.

Other Republicans, however, remained wary or opposed to impeachment, including most of those currently in office. Sen. Roy Blunt (R-Mo.) suggested it was not necessary because there was little chance Trump would repeat his dangerous actions.

“Now, my personal view is that the president touched the hot stove on Wednesday and is unlikely to touch it again. And if that’s the case, I think we — we get — ” Blunt said, trailing off.

Then, he added: “Every day we get closer to the last day of his presidency, we should be thinking more about the first day of the next presidency than the last day of his presidency.”

Amy B Wang and Annie Linskey contributed to this report.