House Republican Conference Chair Liz Cheney -- the No. 3 Republican in the House and highest-ranking woman in the Republican Party -- has announced she will vote to impeach Trump for inciting an insurrection at the Capitol.

"Much more will become clear in coming days and weeks, but what we know now is enough," she said in a statement. "The President of the United States summoned this mob, assembled the mob, and lit the flame of this attack. Everything that followed was his doing. None of this would have happened without the President. The President could have immediately and forcefully intervened to stop the violence. He did not."

"There has never been a greater betrayal by a President of the United States of his office and his oath to the Constitution," she said.

Her announcement follows Republican Rep. John Katko of New York becoming the first House Republican to say he will support House Democrats' efforts to remove Trump from office through impeachment.

Republican Rep. John Katko of New York has released a statement saying he will vote to impeach Trump -- becoming the first Republican to publicly voice an expected vote to remove the president from office.

Katko joins at least 218 House Democrats who have signed onto a resolution charging Trump with inciting an insurrection. A House vote could happen as early as Wednesday, one week before Biden's inauguration at the Capitol.

“To allow the president of the United States to incite this attack without consequence is a direct threat to the future of our democracy,” Katko said in the statement. “For that reason, I cannot sit by without taking action. I will vote to impeach this president."

No House Republicans voted to impeach Trump in 2019.

-ABC News' Benjamin Siegel

The first confirmation hearing for one of Biden's Cabinet picks is officially on the Senate schedule for the day before his inauguration -- which is also the earliest day the Senate is likely to accept an impeachment article against Trump from the House.

Department of Homeland Secretary nominee Alejandro Mayorkas' hearing will be at 10 a.m. on Tuesday, Jan. 19, the Senate Homeland Security and Governmental Affairs Committee announced Tuesday.

In the wake of the siege on the Capitol, the incoming Biden administration is making a push to prioritize confirmations for national security nominees, so those officials may assume their roles as early as next week.

Traditionally, the Senate has confirmed national security nominees on Inauguration Day, and did so for Department of Homeland Security secretary nominees in both 2009 and 2017.

Capitol Police have added new security measures to the House of Representatives -- requiring that all members and staff go through metal detectors before they enter the chamber, according to a new memo sent to offices by the acting House Sergeant at Arms.

The memo comes ahead of a vote Tuesday evening on a resolution pressing Vice President Mike Pence to mobilize the Cabinet and invoke the 25th Amendment to remove Trump from office.

Currently, visitors and staff are screened when they enter the Capitol building, but members of Congress are not. There are already metal detectors in place for visitors to the House galleries, which had been shuttered since March because of the pandemic.

Several lawmakers continue to worry about their safety in the wake of last week's Capitol riot -- and Democrats in control of the chamber have expressed concerns about some GOP colleagues and their alleged connections to the organizers. Some Republicans, most notably Rep. Lauren Boebert, R-Colo. have been outspoken about carrying weapons around the Capitol.

"Failure to complete screening or the carrying of prohibited items could result in denial of access to the Chamber," acting Sergeant at Arms Timothy Blodget wrote in the memo.

-ABC News' Benjamin Siegel and Mariam Khan

Although South Dakota Rep. Dusty Johnson said that Trump deserves “more than his fair share of blame” for the U.S. Capitol riot last week, he voted not to impeach the president Wednesday.

Johnson told ABC News that his decision was based on due process of the law.

“I think due process matters,” said Johnson. “I just felt like a snap impeachment was not in the best interest of the country.”

He said Trump could have been held accountable through censure.

“Impeachment for someone who is out of office looks like some sort of formal reprimand. Really, you can’t kick them out when they’re already gone,” said Johnson. “I think (Nancy Pelosi) could have gotten 100 Republican votes for censure.”

Democrats defended the use of impeachment because an impeachment and a conviction vote by two-thirds of the Senate would open Trump up to a congressional ban on running for federal office. Trump has already indicated that he would run for office again in 2024.

Johnson said that he and “dozens” of his Republican colleagues felt frustrated on the House floor Wednesday. He said that his fellow Democrats missed an opportunity to work across the aisle.

“The rhetoric on the House floor today was the most toxic I have seen in my two years. It was the most rancorous,” he said. “And that’s one of the reasons why I was trying to get some of my Democratic colleagues more interested in a bipartisan censure, a more unifying approach than, I think, a largely single-party impeachment process.”

-ABC News Haley Yamada