They alleged that Trump was the one who incited his supporters to storm the Capitol Hill.
The Capitol building was stormed on January 6 after thousands of supporters of Trump gathered in support of false claims that widespread fraud denied him victory in last November’s presidential election.
Five people died, including a Capitol police officer, as the mob breached the building where the November 3 election result was being certified.
The US Senate began the impeachment trial of Trump, a Republican, on Wednesday with impeachment managers from the Democratic Party-controlled House of Representatives making a strong case against the former president accusing him of inciting the insurrection.
Nine impeachment managers of the Democratic Party showed a number of chilling video footage from the January 6 attack to argue that Trump needs to be impeached.
They described the attack as one of the darkest chapters in American history.
They also showed previously undisclosed and chilling security camera footage of the mayhem.
“If you think this is not impeachable, what is? What would be?” said Representative Jamie Raskin, the lead House impeachment manager.
“If you don’t find this a high crime and misdemeanour today, you have set a new, terrible standard for presidential misconduct in the United States of America.”
The managers also warned that failure to convict Trump would set a dangerous precedent that future presidents could exploit.
“We humbly, humbly ask you to convict President Trump for the crime for which he is overwhelmingly guilty of,” said Congressman Joe Neguse.
“Because if you don’t – if we pretend this didn’t happen, or worse, if we let it go unanswered – who’s to say it won’t happen again?”
Lawyers for Trump are scheduled to begin their counter- argument on Friday.
Like the Democrats, they have 16 hours spread over the next two days – Friday and Saturday – to present their case.
However, political pundits said that Trump is likely to be acquitted for the second time.
Trump lost the elections to Joe Biden, who was sworn in as the 46th president on January 20.
While the House, where the Democrats have the majority, impeached him before January 20, when he was still the president, the Senate impeachment trial has begun three weeks after he left office.
This is for the first time in American history that a former US president is being impeached. Trump, 74, is also the first president ever to have been impeached twice.
A two-thirds majority is needed to convict Trump, meaning 17 Republicans would have to vote with the Democrats in the 100-member Senate where both parties have 50 seats each.
By Thursday, Democrats were expecting support from five or six Republican Senators, still short of 11 to get to the magic figure.
However, the Democrats through liberal use of harrowing videos of the January 6 attack were successful in touching the emotional cord of the Republican Senators.
“That was a pretty emotional – emotional – presentation,” said Republican Senator John Cornyn.
Making a passionate case for the impeachment of Trump, Democrats argued that acquittal of the former president would erode America’s standing as a beacon of democracy in the world.
“President Trump declared his conduct totally appropriate. So if he gets back into the office, and it happens again, we’ll have no one to blame but ourselves,” Congressman Raskin said on the Senate floor Thursday.
Congressman David Nicola Cicilline said that documents show that the rioters said they would have killed former vice president Mike Pence and House Speaker Nancy Pelosi had they found them.
Lawyers for Trump argued that it was unconstitutional to put a former president through the process at all and accused Democrats of being politically motivated.