Speaking after Vice President Mike Pence, Senate Majority Leader Mitch McConnell said, "the United States Senate will not be intimidated."

"We will not be kept out of this chamber by thugs, mobs, or threats. We will not bow to lawlessness or intimidation. We are back at our posts. We will discharge our duty under the Constitution and for our nation, and we are going to do it tonight," he said.

While McConnell condemned the violence, he also seemed to downplay the threat at the Capitol Wednesday, saying, "the United States and the United States Congress have faced down much greater threats than the unhinged crowd we saw today."

"We will certify the winner of the 2020 presidential election. Criminal behavior will never dominate the United States Congress," McConnell added. "This institution is resilient. Our democratic republic is strong. The American people deserve nothing less."

Vice President Mike Pence opened the joint session shortly after 8 p.m. with a brief statement after hours of chaos and riots ravaged the U.S. Capitol complex.

"The Senate will come to order," Pence began. "Today was a dark day in the history of the United States Capitol. But thanks to the swift efforts of U.S. Capitol Police, federal, state, and local law enforcement, the violence was quelled."

"The Capitol is secured, and the people’s work continues. We condemn the violence that took place here in the strongest possible terms," he continued. "We grieve the loss of life in these hallowed halls, as well as the injuries suffered by those who defended our Capitol today. And we will always be grateful to the men and women who stayed at their posts to defend this historic place," he said.

"To those who wreaked havoc in our Capitol today, you did not win. Violence never wins. Freedom wins, and this is still the people's house. And as we reconvene in this chamber, the world will again witness the resilience and strength of our democracy," he continued. "For even in the wake of unprecedented violence and vandalism at this Capitol, the elected representatives of the people of the United States have assembled again, on the very same day, to support and defend the Constitution of the United States."

"Let's get back to work," he added to applause.

Stephanie Grisham, Melania Trump's chief of staff and the former White House press secretary has resigned in the wake of violent protests in Washington Wednesday.

“It has been an honor to serve the country in the White House. I am very proud to have been a part of Mrs. Trump’s mission to help children everywhere, and proud of the many accomplishments of this Administration," Grisham told ABC News in a statement.

-ABC News' John Santucci

In a "Dear Colleague" letter Wednesday evening, House Speaker Nancy Pelosi called the breach of the U.S. Capitol "a shameful assault was made on our democracy" but said it wouldn't deter lawmakers from carrying out their duties.

"To that end, in consultation with Leader Hoyer and Whip Clyburn and after calls to the Pentagon, the Justice Department and the Vice President, we have decided we should proceed tonight at the Capitol once it is cleared for use," she wrote.

"We also knew that we would be a part of history in a positive way, today, despite ill-founded objections to the Electoral College vote. We now will be part of history, as such a shameful picture of our country was put out to the world, instigated at the highest level," Pelosi continued.

"Members and staff should remain on the Capitol complex until they are notified by the United States Capitol Police. I look forward to seeing you later this evening, during this time of great sadness," she said.

-ABC News' Mary Bruce

House Speaker Nancy Pelosi, in a new letter to Democrats on Saturday, asked members to prepare to return to Washington this week -- another signal that the House could take up and pass the impeachment article to the Senate after it is formally introduced on Monday.

Pelosi thanked fellow Democratic representatives for speaking with her on a conference call Friday and said she was taking their considerations into account. She did not specifically mention voting on impeachment in the letter, though.

"Since that call, I have received scores of communications from Members expressing your views about how we go forward and regarding a strong presence of our Caucus in the Capitol," she wrote. "Over the last few days, I have discussed your views with Constitutional lawyers, both inside and outside the Congress, to consider the parliamentary and constitutional options available to us."

"From what I have heard from Members, and from the deluge that I have received from the public, it is clear that, once again, the Times Have Found Us to save our democracy," Pelosi added in the letter. "We will be proceeding with meetings with Members and Constitutional experts and others. I continue to welcome your comments. I urge you to be prepared to return to Washington this week."

While Democrats are hopeful Republicans will back their effort, none have come out and said they would back the charge as drafted.

Pelosi said at a press conference on Thursday, "If the Vice President and Cabinet do not act [on the 25th Amendment], the Congress may be prepared to move forward with impeachment."

Some Democrats planned to connect with Republican colleagues this weekend to gauge their support and encourage them to back the effort.

-ABC News' Benjamin Siegel