With at least five Republicans joining their push to impeach President Donald Trump over the storming of the US Capitol, Democrats in the House of Representatives stood poised for a history-making vote to try to remove the president from office.
With eight days remaining in Trump's term, the House will vote on Wednesday on an article of impeachment accusing the Republican of inciting insurrection in a speech to his followers last week before a mob of them stormed the Capitol, leaving five dead.
That would trigger a trial in the still Republican-controlled Senate, although it was unclear whether enough time or political appetite remained to expel Trump.
Democrats moved forward on an impeachment vote after an effort to persuade Vice President Mike Pence to invoke the 25th Amendment of the U.S. Constitution to remove Trump was rejected by Pence on Tuesday evening.
"I do not believe that such a course of action is in the best interest of our Nation or consistent with our Constitution," Pence said in a letter to House Speaker Nancy Pelosi.
Despite the letter, the House passed a resolution formally calling on Pence to act. The final vote was 223-205 in favour.
While that was occurring, Trump's iron grip on his party was showing further signs of slipping as at least four Republicans, including a member of the House leadership, said they would vote for his second impeachment - a prospect no president before Trump has faced.
Representative Liz Cheney, the No. 3 House Republican, said: "There has never been a greater betrayal by a President of the United States of his office and his oath to the Constitution."
Trump "summoned this mob, assembled the mob, and lit the flame of this attack" on the Capitol on Jan. 6, Cheney, the daughter of former Republican Vice President Dick Cheney, said in a statement, adding: "I will vote to impeach the president."
Three other Republican House members, John Katko, Adam Kinzinger and Fred Upton, said they would also vote for impeachment.
Republican leaders in the House did not urge their members to vote against impeaching Trump, saying it was a matter of individual conscience.