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

House Democrats have opened an investigation into what law enforcement and the intelligence community knew about threats to the Capitol ahead of the Jan. 6 siege.

The investigation from the House Intelligence, Oversight, Homeland Security and Judiciary committees will also examine whether anyone with security clearances -- current or former National Security, Defense, Justice or Homeland Security officials -- participated in the riot.

The investigation will also examine the federal law enforcement response in the aftermath of the attack.

"The Committees will conduct robust oversight to understand what warning signs may have been missed, determine whether there were systemic failures, and consider how to best address countering domestic violent extremism, including remedying any gaps in legislation or policy," committee members wrote in a letter to the FBI, DHS and Office of the Director of National Intelligence.

"This still-emerging story is one of astounding bravery by some U.S. Capitol Police and other officers; of staggering treachery by violent criminals; and of apparent and high-level failures -- in particular, with respect to intelligence and security preparedness," the letter later stated.

Democrats plan to request documents and briefings from administration officials as part of the investigation -- just one of several looking into the Capitol attack.

-ABC News' Benjamin Siegel