As procedural votes were underway in the House, Speaker Nancy Pelosi went outside the Capitol to thank the National Guard troops deployed to the complex in the wake of last week's riot and ahead of Biden's inauguration in one week.

Some National Guard members inside the Capitol were spotted taking in the sights of the Rotunda Wednesday morning, gathering around and listening to Rep. Brian Mast, R-Fla., an Army veteran who lost both legs in Afghanistan.

The Capitol has been closed to tours for months due to the coronavirus pandemic. With the exception of last Wednesday's attack, this is one of the few times visitors have snapped photos inside the building during the pandemic -- finding themselves with unique access as they've been designated to protect the building and lawmakers.

As lawmakers arrived on the Hill ahead of the House gaveling in to consider Trump's second impeachment, a heavy National Guard presence greeted them both outside and inside the building -- with some resting, embracing their rifles, on the floor of the Capitol.

Jane Campbell, the president and CEO of the United States Capitol Historical Society, confirmed to ABC News that troops have not been quartered in the Capitol since the Civil War -- when the Rotunda was still under construction, and the open-air space was used as a field hospital.

A Defense official said the National Guard members seen sleeping at the Capitol are on breaks and noted that it’s not uncommon on domestic or overseas deployments to see members taking breaks in between long shifts.

There are currently 6,600 members of the National Guard in Washington, D.C. with more continuing to flow in. A Defense official said Wednesday afternoon that the National Guard has now been authorized to have up to 20,000 Guardsmen in Washington for inauguration security and that most may be in town by this weekend.

-ABC News Luis Martinez and Benjamin Siegel

The first vote broke down along party lines 221-205, with Democrats voting to advance proceedings. Seven House members did not vote.

The House is now voting on the rule, which is expected to take roughly 45 minutes to one hour, the same amount of time. The chamber will then move to begin debate on the impeachment article.

-ABC News' Benjamin Siegel

As part of rule debate leading up to debate on the article of impeachment, Republicans have largely focused on procedural concerns, criticizing Democrats for moving quickly to impeach Trump without a full investigation and suggesting the move would further divide Americans.

"I hold him accountable for the attack on the Capitol," newly elected Rep. Nancy Mace, R-S.C., said, making her first speech on the House floor.

"If we're serious about healing the divisions in this country, Republicans and Democrats need to recognize that last week wasn't the first day of violence," she continued. "There is violence on both sides of the aisle."

"President Trump will leave office in seven days," Rep. Jason Smith, R-MO, said. "This is a reckless impeachment ... have a conscience."

Rep. Jim Jordan, R-Ohio, attacked Democrat Rep. Jim McGovern, the chairman of the House Rules Committee, over his 2017 objection to the election results, and accused Democrats of hypocrisy.

McGovern quickly shot back that Democrats and Hillary Clinton recognized Trump's victory -- when Republicans refused to acknowledge Biden's.

"The bottom line is this. This Capitol was stormed -- people died because of the big lies that were being told by this president and by too many other people on this side of the aisle. Enough!" McGovern said. "Coming up on this floor and talking about whataboutism and trying to make these false equivalences -- give me a break."

"The president of the United States instigated an attempted coup in this country," he added. "If this is not an impeachable offense I don't know what the hell is."

-ABC News' Benjamin Siegel

Several conservative House Republicans have criticized Rep. Liz Cheney since she announced she would support impeachment Tuesday evening.

The Wyoming Republican is the chair of the House GOP conference -- the No. 3 leadership position -- and was reelected to by GOP members at the start of this Congress.

"We ought to have a second vote," Rep. Jim Jordan, R-Ohio, told reporters Wednesday about the leadership position. "The conference ought to vote on that."

"She should not be serving this conference," Rep. Andy Biggs, R-Ariz., said Tuesday.

It's unclear how widespread the effort to remove Cheney from GOP leadership is. But Trump's top allies in the House are using impeachment as an opportunity to kneecap Cheney, a potential future speaker, after months of simmering tensions.

-ABC News' Benjamin Siegel

While House Democrats take action to remove Trump from office after he encouraged supporters to march on Capitol Hill last week.

Trump on Monday plans to award the Presidential Medal of Freedom -- the nation's highest civilian honor -- to GOP Rep. Jim Jordan of Ohio, his longtime defender, in a closed event, something not the event not mentioned on his schedule, a White House official said. Later in the week, he's expected to bestow the same honor on New England Patriots head coach Bill Belichick.

Sources told ABC News over the weekend the White House is building out a week of programming to highlight Trump’s record over the dwindling days of his administration, despite amplified calls for Trump to resign or risk facing a second impeachment. Appearing to dismiss those calls, Trump has a trip planned for Tuesday to Texas to showcase the border wall he's pushed hard for, and is expected to host events in the next week to highlight what sources say are the administration's achievements in areas including foreign affairs, business and pandemic response.

The president was angry for much of this past weekend -- mostly about Twitter permanently suspending his account on Friday, according to sources who have spoken directly to Trump. Sources said the president is expected to depart Washington before Biden takes the oath of office on Jan. 20.

While Biden said last week it’s a "good thing" Trump isn’t attending his inauguration, he hasn’t said whether he supports impeaching Trump, deflecting that decision to Congress instead. Biden's said he wants the incoming Congress to focus on his Cabinet nominations and pandemic relief from the onset, but an impeachment trial in the Senate risks preempting the rest of its business.

On Monday, Biden is slated to meet with transition and economic advisors and will publicly receive the second dose of the COVID-19 vaccine from Wilmington, Delaware, in the afternoon.

-ABC News Chief White House Correspondent, John Santucci and Katherine Faulders