WASHINGTON • The House of Representatives has made Mr Donald Trump the first US president to be impeached twice, formally charging him on Wednesday with inciting an insurrection, a week after a violent mob of his supporters stormed the Capitol.
Here is a guide to what will happen next.
Q: Are the impeachment proceedings over?
A: No. Impeachment refers only to the House, the lower chamber of Congress, bringing charges. The next major step is for the Senate, the upper chamber, to have a trial to determine Mr Trump's guilt.
A two-thirds majority is needed to convict Mr Trump. If all 100 senators are present for the vote, at least 17 Republicans need to join the Democrats to convict him.
Q: When will the trial begin?
A: The Senate's Republican Majority Leader Mitch McConnell has rejected Democratic calls for an immediate impeachment trial, and said it cannot begin until after the Senate returns from a recess on Jan 19.
That means the trial will likely begin after Mr Trump leaves office on Jan 20. The House must formally transmit the charge to the Senate before the trial can begin.
Q: What is Mr Trump's likely defence in the Senate trial?
A: The House approved a single article of impeachment - a formal charge - accusing Mr Trump of "incitement of insurrection", focused on a speech he gave to thousands of supporters before the mob rampaged through the Capitol.
Mr Trump is likely to argue that his remarks were free speech protected by the Constitution's First Amendment and that, while he told supporters to "fight", he did not intend it as a literal call to violence.
He released a video statement on Wednesday, after the impeachment vote, saying he condemned the violence.
"Violence and vandalism have absolutely no place in our country and no place in our movement," he said.
Q: Can a former president be impeached?
A: Yes. The consensus among scholars is that a "late impeachment" is constitutional.
Scholars note that impeachment is used not just to remove officials from office, but also to disqualify them from future office, so there is still a reason to try Mr Trump after he leaves the White House.
The Constitution states that one penalty is "disqualification to hold and enjoy any office of honour, trust or profit under the United States".
Under Senate precedent, only a simple majority of the Senate is needed for disqua-lification. Historically, that vote happens only after a conviction.
Q: How long will the trial last?
A: The US Supreme Court has said that the Senate has wide latitude to set its own rules for how to conduct an impeachment. But under current rules, a trial would take at least a few days.
Q: Are there precedents for disqualification from future office through impeachment?
A: In US history, only three federal officials have ever been disqualified through impeachment proceedings. All three were federal judges.
Most recently, in 2010, the Senate removed and disqualified from future office a Louisiana judge found to have engaged in corruption.
There is some debate over the scope of the disqualification clause and whether it applies to the presidency, said law professor Brian Kalt of Michigan State University.
Analysing historical documents, some law experts say the founders did not intend the presidency to be considered an "office" under the disqualification clause, while others argue that the term applies.
Q: Can Mr Trump be disqualified if he is not convicted by the Senate?
A: It is not immediately clear if someone must be convicted to be disqualified. This is uncharted legal territory, and there is no clear answer, according to scholars.
Constitutional law professor Paul Campos of the University of Colorado said he believed that a vote to disqualify Mr Trump can be held even if there are not enough votes for conviction, given the Senate's wide latitude to determine how it conducts a trial.
But Prof Kalt said he thought disqualification would require conviction first. To do otherwise would be the equivalent of punishing the president for an offence he did not commit, he said.
All three judges who were disqualified from office were first convicted.
Q: What about the 14th Amendment?
A: Section 3 of the 14th Amendment provides an alternative path for disqualification.
The provision states that no person shall hold office if they have engaged in "insurrection or rebellion" against the United States. It was enacted following the Civil War to bar Confederates from holding public office.
Under congressional precedent, only a simple majority of both chambers is needed to invoke this penalty. Congress can later remove the disqualification, but only if two-thirds of both houses vote in favour of doing so.
In 1919, Congress used the 14th Amendment to block elected official Victor Berger from assuming his seat in the House because he had actively opposed US intervention in World War I.
The text of Section 3 of the 14th Amendment does not explain how it should be invoked.
Another section of the 14th Amendment, Section 5, empowers Congress to enforce the entire amendment through "appropriate legislation".
Some scholars have interpreted this language to mean that a majority of both chambers of Congress could enact a law applying a ban to a particular president, such as Mr Trump.
"The 14th Amendment route is very unclear as to what it would take to get it rolling," Prof Kalt said. "I think it would require some combination of legislation and litigation."
Q: Could Mr Trump challenge a disqualification in court? A It is certainly possible, according to Prof Kalt.
A: Supreme Court case from 1993 makes clear that the court is wary of second-guessing how the Senate handles impeachment.
In that case, involving an accused judge, the court said that whether the Senate had properly tried an impeachment was a political question and could not be litigated.
If Mr Trump is disqualified, the current Supreme Court might want to clarify whether the move was lawful, Prof Kalt said.
Mr Trump appointed three of the Supreme Court's nine members: Justices Neil Gorsuch, Brett Kavanaugh and, most recently, Amy Coney Barrett. The court now has a six-judge conservative majority.
"If you are going to say someone can't run, you want to get that litigated and settled sooner rather than later," Prof Kalt said.