Democrats launched a bid on Monday to impeach President Donald Trump for a second time over his role in last week's attack on the US Capitol. House Speaker Nancy Pelosi has said Democrats will proceed with impeachment proceedings if the US vice president refuses to declare Trump unfit for office.
Democrats first introduced a resolution urging Vice President Mike Pence to invoke the 25th Amendment - which would deem Trump unfit to perform his duties. Republicans swiftly objected to the move, blocking it from being immediately voted on.
Democrats responded in kind by introducing an article of impeachment against Trump, charging him with "incitement of insurrection" after his supporters stormed the US Capitol on Wednesday. Lawmakers in the House of Representatives could vote on the Pence measure on Tuesday, after Republicans blocked it.
If the appeal to Pence fails - which is considered the most likely outcome, the Democrat-controlled House will press forward with plans to impeach Trump. A vote on moving forward impeachment proceedings could take place as soon as Wednesday. If impeachment proceedings are launched, lawmakers in the House will vote whether to bring charges - known as the "articles of impeachment" - against Trump. If a simple majority of the House's 435 members votes in favor of the charges, the process moves to the Senate.
A two-thirds vote in the chamber is needed to convict and remove a president - but with Trump leaving office in a matter of days, removal isn't the high priority.
Should the house vote to impeach (or charge) Trump, there's a high possibility that he would be disqualified from future public office - barring him from running for president again.
Trump, who is scheduled to leave office on January 20, has received sharp criticism following the violence in and around the US Capitol building on Wednesday. Trump has been accused of inciting the violence, by addressing a large rally on the National Mall in front of the US Capitol, saying he would join them when they "walk down to the Capitol" earlier that day.
Since losing the November 3 election, Trump has falsely claimed he was the victim of widespread fraud.
Pelosi told American broadcaster CBS in an interview on Sunday that "the person that's running the executive branch is a deranged, unhinged, dangerous president of the United States."
Trump was previously impeached under two articles: abuse of power and obstruction of Congress in regards to allegations that Trump sought to discredit then-Democratic candidate Joe Biden
in the lead up to the 2020 US presidential election.
The articles were written up in 2019 and the trial was held in January 2020. The Republican-controlled Senate did not find him guilty of either article.
A two-thirds majority is required for a conviction.