In a letter to House Speaker Nancy Pelosi, Vice President Mike Pence said he would not invoke the 25th Amendment and remove the president.

"I am grateful for the leadership that you and other congressional leaders provided in reconvening Congress to complete the people's business on the very same day. It was a moment that demonstrated to the American people the unity that is still possible in Congress when it is needed most," he wrote. "But now, with just eight days left in the President's term, you and the Democratic Caucus are demanding that the Cabinet and I invoke the 25th Amendment. I do not believe that such a course of action is in the best interest of our Nation or consistent with our Constitution."

He continued, "Last week I did not yield to pressure to exert power beyond my constitutional authority to determine the outcome of the election, and I will not now yield to efforts in the House of Representatives to play political games at a time so serious in the life of our Nation."

In conclusion, he urged Pelosi and members of Congress to avoid actions that would further divide and inflame the passions of the moment.

"Work with us to lower the temperature and unite our country as we prepare to inaugurate President-elect Joe Biden as the next President of the United States. I pledge to you that I will continue to do my part to work in good faith with the incoming administration to ensure an orderly transition of power. So help me God," he wrote.

The House of Representatives is debating a resolution urging Vice President Mike Pence to invoke the 25th Amendment and remove Trump from office over his role in last week's attack on the Capitol.

With Democrats holding a majority in the chamber, the measure is expected to pass. However, Pence given no public indication that he plans to take action.

Democrats are expected, then, to move forward with impeaching Trump on one article -- charging him with "inciting an insurrection." At least 218 Democrats and three House Republicans have indicated their support to impeach the president.

-ABC News' Mariam Khan

The House Judiciary Committee has released a 76-page staff report laying out Democrats' case for impeaching Trump over his role in the violent attack on the U.S. Capitol last week.

"President Trump has falsely asserted he won the 2020 presidential election and repeatedly sought to overturn the results of the election. As his efforts failed again and again, President Trump continued a parallel course of conduct that foreseeably resulted in the imminent lawless actions of his supporters, who attacked the Capitol and the Congress. This course of conduct, viewed within the context of his past actions and other attempts to subvert the presidential election, demonstrate that President Trump remains a clear and present danger to the Constitution and our democracy," an excerpt from the report reads.

"The House must reject this outrageous attempt to overturn the election and this incitement of violence by a sitting president against his own government. President Trump committed a high Crime and Misdemeanor against the Nation by inciting an insurrection at the Capitol in an attempt to overturn the results of the 2020 Presidential Election," it concludes.

The House is expected to vote to impeach Trump as early as Wednesday -- making him the first president in history to be impeached twice.

-ABC News' Katherine Faulders

Senate Majority Leader Mitch McConnell has privately acknowledged he believes Trump committed impeachable offenses and that he is pleased Democrats are moving to impeach him, believing it will make it easier for the Republican Party to be rid of Trump, a source confirmed to ABC News.

The New York Times first reported the development.

McConnell has not said publicly whether he'd vote to impeach Trump and a McConnell spokesman declined to comment.

At least three House Republicans -- Rep. Liz Cheney, Wyo., Rep. John Katko, R-N.Y. and Rep. Adam Kinzinger, R-Ill. -- have said they will vote to impeach the president.

-ABC News' Trish Turner

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