President Trump’s lawyers have begun defending him at his impeachment trial, accusing Democrats of seeking to overturn the result of the 2016 election.
“The president did absolutely nothing wrong,” White House Counsel Pat Cipollone said.
Mr Trump’s defence will last three days and follows the Democrats’ prosecution case which ended on Friday.
The president faces two charges linked to his dealings with Ukraine.
The charges, or articles of impeachment, accuse him of abuse of power and obstruction of Congress.
He is alleged to have withheld military aid to pressure the Ukrainian President, Volodymyr Zelensky, into starting a corruption investigation into Mr Trump’s political rival, Democrat Joe Biden, and his son Hunter.
Democrats also accuse Mr Trump of making a visit by Mr Zelensky to the White House contingent on an investigation.
Mr Trump is charged with obstructing Congress by failing to co-operate with the House of Representatives impeachment inquiry.
The president dismisses the accusations as a witch-hunt.
What else did the defence say?
The trial in the Senate will decide if Mr Trump should be removed from office. This is unlikely as the Republicans control the Senate and any such move would need a two-thirds majority.
Echoing a line heard from many Republicans, Mr Cipollone said Democrats were “asking you not only to overturn the results of the last election… they’re asking you to remove President Trump from the ballot in the election that’s occurring in approximately nine months.”
“They are asking you to do something very, very consequential and, I would submit to you … very, very dangerous,” he said.
Much of the abuse of power charge centres on a phone call in July between Mr Trump and Mr Zelenksy.
Trump defence lawyer Mike Purpura insisted there was no quid pro quo – as asserted by the Democrats.
“Zelenksy felt no pressure. President Zelensky says he felt no pressure. The House managers tell you they know better,” he said.
What have the Democrats been saying?
Adam Schiff, the Democrat chair of the House Intelligence Committee wrapped up the prosecution on Friday, warning that Mr Trump would commit abuse of power again if allowed to remain in office.
In a sometimes emotional address, he said: “You can’t trust this president to do what’s right for this country.”
“If you find him guilty, you must find that he should be removed.”
Where does the trial go from here?
Saturday’s session was unexpectedly short – two hours. The second day of defence arguments resumes on Monday at 13:00 local time (18:00 GMT) allowing for a short weekend break.
Next week will also see senators return to the thorny issue of allowing new witnesses to be called and fresh evidence submitted.
The Republicans oppose hearing more testimony as they push for a quick trial.
But the leader of the Democrats in the Senate, Chuck Schumer, told reporters after Saturday’s hearing that Mr Trump’s defence team had inadvertently “made a really compelling case for why the Senate should call witnesses and documents”.