The historic trial of Donald Trump has begun in the US Senate with Democratic prosecutors from the House of Representatives and his lawyers sparred, while the US President was 6,500 kilometres away in Davos hobnobbing with the world's elite.
The first order of business for Republicans, who control the Senate, and the Democrats first order of business when the trial began on Tuesday was coming up with rules procedure, including the calling of witnesses.
The Republican leader of the Senate, Mitch McConnell, who setting the rules, said as the trial began, "This initial step will offer an early signal to our country: Can the Senate still serve our (nation's) founding purpose?"
The rules will have to be voted on by the 100-member Senate, where the Republicans have a 53-member lead.
McConnell - like Trump - wants an early end to the trial, preferably before February 4 when Trump's State of the Union address is scheduled.
Three Democrat senators seeking the party's presidential nomination are locked up in the trial while their rivals are able to campaign, especially in Iowa where party members will be the first in the nation on February 3 to make their choice.
Notably, former Vice President Joe Biden, who is at the root of the charges against Trump, however, will be able to campaign with an advantage over Senators Bernie Sanders, Amy Klobuchar and Elizabeth Warren.
The charges of abuse of power stem from Trump's request to Ukrainian President Volodymyr Zelentsky during a phone call to investigate the actions of Biden and his son, Hunter, in Ukraine.
Calling new witnesses that the Democrats want will extend the duration of the trial.
McConnell has said that he has enough votes ensure control over the rules and process, although he has made two changes to accommodate some moderate party members.
However, even if there are defections from his party Trump's acquittal is almost a certainty because a two-thirds majority is required for convicting him.
The only two other presidents - Bill Clinton in 1998 and Andrew Johnson in 1868 - to be impeached before Trump were both acquitted since the opposition could not muster the two-thirds vote for conviction.
Adam Schiff, the House Intelligence Committee chair, who is leading the prosecution, and Senate Democratic Party Leader Chuck Schumer demanded that they be allowed to call witnesses and introduce more evidence.
Schumer said the rules proposed McConnell to bar witnesses and new evidence "will result in a rushed trial with little evidence in the dark of night."
The Democrats did not allow the Republicans to call their own witnesses during the impeachment investigations and hearings in the House and the Republican leaders want to do the same to them.
Schiff said, "Right now a great many, perhaps even most Americans, do not believe there will be a fair trial. They don't believe that the Senate will be impartial. They believe that the result is precooked."
He called Trump's defence "nonsense."
White House lawyer Pat Cipollone questioned the motives of the Democrats in launching the impeachment.
He said, "A partisan impeachment is like stealing an election. ... They want to remove Trump from the ballot, but they don't have the guts to tell you that."
The Democrats want former National Security Adviser John Bolton, Trump's Chief of Staff Mick Mulvaney and others who have knowledge of Trump's request for Ukrainian investigation of the Bidens to testify.
Trump wants Biden to testify on his role in the firing of a prosecutor investigating his son's Ukrainian company.
The debate on the rules resolution is expected to stretch late with a vote taking place late Tuesday night or in the early hours of Wednesday.
If the rules are adopted, the House prosecutors are likely to start on Wednesday their three days of arguments laying their case Trump on charges of abuse of power and obstruction of Congress.
Trump's lawyers will have three more days for counter-arguments.
It will be followed by 16 hours of questions from Senators and fours hours of deliberations, after which a vote on new witnesses and documents.
One of the House prosecutors Zoe Lofgren, who had participated in the impeachment of Clinton, said that Clinton had provided documents to the House probe, while Trump had not.
Therefore, she said, Trump should be compelled to provide them to the Senate.
The Senate has banned its members from using electronic media like mobile phones, tablets or computers and senators could be seen making notes on paper.
But the prosecutors and defence used Powerpoint-type displays to make their case.
Senators are also ordered to stay silent on pain of punishment.