US senators on Tuesday voted to go ahead with Donald Trump's impeachment trial on a charge of inciting the deadly assault on the Capitol after viewing graphic video of the January attack.
The Senate voted 56-44 to proceed with its trial of the former president, a historic first, rejecting largely along party lines his lawyers' argument that a president cannot face trial after leaving the White House.
Democrats hope to disqualify Mr Trump from ever holding public office again.
The video presented by the nine House Democrats interspersed images of the January 6 Capitol violence with clips of Mr Trump's incendiary speech to a crowd of supporters moments earlier.
In it, he urged them to "fight like hell" to overturn his November 3 election defeat.
Senators, serving as jurors, watched as screens showed Mr Trump's followers pulling down barriers and hitting police officers at the Capitol.
The video also included the moment when police guarding the House chamber fatally shot protester Ashli Babbitt, one of five people including a police officer who died in the rampage.
The mob attacked police, sent legislators scrambling for safety and interrupted the formal congressional certification of President Joe Biden's victory.
It came after Mr Trump spent two months challenging the election results based on unsubstantiated claims of voting fraud.
"If that's not an impeachment offence, then there is no such thing," Jamie Raskin, the Democrat who led the prosecution, told the senators after the video.
Mr Raskin wept as he recounted how relatives he took to the Capitol that day to see the certification had to shelter in an office near the House floor.
"They thought they were going to die," he said.
In contrast to the Democrats' emotional presentation, Mr Trump's lawyers attacked the process, saying the proceedings were an unconstitutional, partisan effort to end Mr Trump's political future even after he had left the White House.
"What they really want to accomplish here in the name of the constitution is to bar Donald Trump from ever running for political office again," David Schoen, one of Trump's lawyers, told senators.
"But this is an affront to the constitution, no matter who they target today."
Mr Schoen denounced the "insatiable lust for impeachment" among Democrats before airing his own video of various Democratic politicians calling for Mr Trump's impeachment going back to 2017.
He was impeached by the Democratic-led House on January 13 on a charge of inciting an insurrection, although his conviction remains unlikely.
Finding Mr Trump guilty would require a two-thirds majority, meaning at least 17 Republicans would need to join the Senate's 48 Democrats and two independents in voting against him.
who remains his party's most powerful figure even out of office.
Mr Trump is the only president to go on trial in the Senate after leaving office and the only one to be impeached twice. He is the third president in US history to be impeached.
The trial was held with extraordinary security around the Capitol, including armed security forces and a perimeter of fencing and razor wire.
Mr Trump's defence team said he was exercising his right to free speech under the constitution's First Amendment when he addressed supporters before the Capitol attack.
"We can't possibly be suggesting that we punish people for political speech in this country," said Bruce Castor, another of Mr Trump's lawyers.
Mr Castor said the storming of the Capitol "should be denounced in the most vigorous terms", but "a small group of criminals", not Mr Trump, were responsible for the violence.
Most legal experts have said it is constitutional to have an impeachment trial after an official has left office.
"Presidents can't inflame insurrection in their final weeks and then walk away like nothing happened," Joe Neguse, a Democratic representative, told the senators.
"And yet that is the rule that President Trump asks you to adopt."
Most of the senators at the trial were in the Capitol on January 6, when many politicians said they feared for their own safety.
Bill Cassidy, a Republican senator, called the Democrats' speeches "a very good opening".
He joined five of his Republican colleagues in finding the proceeding constitutional, reversing his vote from the previous month.
"The arguments they gave were strong arguments," Mr Cassidy said.
The trial could provide clues on the Republican Party's direction after Mr Trump's tumultuous four-year presidency.
Sharp divisions have emerged between Trump loyalists and those hoping to move the party in a new direction.
Democrats are concerned that the trial could impede Mr Biden's ability to swiftly advance an ambitious agenda.
A year ago the Senate, then controlled by the Republicans, acquitted Mr Trump on charges of obstructing Congress and abuse of power by pressuring Ukraine to launch an investigation into Mr Biden and his son, Hunter, in 2019.
