The Democratic-led US House of Representatives has voted to send formal impeachment charges against President Donald Trump to the Senate, where Majority Leader Mitch McConnell has said he would help acquit his fellow Republican at a trial.
Democratic lawmakers, who represent the House majority, voted along party lines on 18 December to impeach Trump over his dealings with Ukraine.
Here is what can be expected in the coming days and weeks:
On Thursday at 12 pm EDT/1700 GMT, the newly appointed House "managers," who will prosecute Trump, will to go to the Senate chamber and read the resolution appointing them and the two articles of impeachment in full.
The charges say Trump abused his power by pressuring Ukraine to investigate former Vice President Joe Biden, a leading Democratic presidential contender for 2020, and that Trump obstructed efforts by Congress to uncover any misconduct.
At 2pm on Thursday, the Senate will take up the articles of impeachment. Supreme Court Chief Justice John Roberts will be escorted into the chamber by the longest-serving Republican senator, Chuck Grassley. Roberts then will swear in the senators as jurors.
Starting 21 January
House managers will present their case against Trump, and the president's legal team will respond, with senators sitting as jurors. McConnell has said the Senate will sit in session six days a week, taking only Sundays off.
Senators would then be given time to submit questions to each side.
McConnell has said that, once the charges are formally submitted to the Senate, he will back a resolution that would set initial rules for the trial but postpone a decision on whether to hear from witnesses.
McConnell has not yet published a draft of the resolution, but he said it would be similar to one adopted in January 1999 during the impeachment of Democratic former President Bill Clinton.
That resolution set deadlines for the prosecution and defense to submit trial briefs that laid out their cases in writing. The resolution also allocated 24 hours for representatives of each side to make oral arguments and set aside 16 hours for senators to ask them questions.
The Clinton resolution referenced by McConnell did not resolve whether witnesses would be called. A follow-up resolution allowing for three witnesses to testify in videotaped depositions passed later along a party-line vote.
Late January to early February
Democrats will push to hear from witnesses during the trial. If McConnell's resolution on initial trial rules is adopted, as expected, senators would likely vote some time after the trial has started on whether to introduce witness testimony sought by the Democrats. Republicans could seek to call witnesses of their own as well, though the White House said on Thursday it didn't think witnesses are necessary.
The Senate now has 53 Republicans, 45 Democrats and two independents who usually vote with the Democrats. That means four Republicans would need to cross party lines and join Democrats in requesting witness testimony.
The trial could continue into February, when Iowa and New Hampshire hold the first nominating contests for the 2020 presidential election. That could pose logistical problems for the four senators seeking the Democratic nomination: Bernie Sanders, Elizabeth Warren, Amy Klobuchar and Michael Bennet.