House Democrats told Republicans they would be setting a “new terrible standard for presidential misconduct” if they acquitted Donald Trump of stoking the January 6 attack on the US Capitol, as they closed out their case in the former president’s impeachment trial.

The warning from the Democratic lawmakers, who were acting as prosecutors in the proceedings, came at the end of two days of allotted time during which they repeatedly showed footage of the deadly assault on Congress and sought to prove that Trump was directly responsible for provoking the mob.

The impeachment managers also tried to bolster their case by offering evidence that Trump had shown no remorse for the attack and had emboldened far-right domestic terrorists to plan more political violence in the future.

“If you think this is not impeachable, what is? What would be?” Jamie Raskin, the congressman from Maryland, asked senators who are acting as de facto jurors in the trial. “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.”

In order for Trump to be convicted, 17 Republicans would have to vote against him along with every Democrat. So far only a handful of senators from Trump’s party have indicated they are leaning in that direction, but Democrats are still hoping that Republicans will pay a political price for failing to punish the former president.

Trump’s defence lawyers — whose first appearance in the proceedings on Tuesday was widely panned — are expected to make their arguments on Friday and possibly into the weekend before the final verdict is rendered.

His attorneys have argued that the trial itself is unconstitutional because Trump is no longer a sitting president, and that the accusations against him violate his right to free speech. But Raskin rejected that claim on Thursday.

“Incitement to violent insurrection is not protected by free speech. There is no First Amendment defence to impeachment for high crimes and misdemeanours. The idea itself is absurd,” he said.

The main focus of the prosecution on Thursday was initially to show that the rioters who attacked the US Capitol were taking direct orders from the former president.

House Democrats cited rioters who claimed they were following Trump’s instructions on the day of the attack and offered examples of the former president’s pattern of encouraging violence against his political opponents.

“Leading up to the attack, the insurrectionists said they were coming to DC for president Trump. He invited them, with clear instructions for a specific time and place, and with clear orders: stop the certification in Congress by any means necessary,” said Diana DeGette, a Democrat from Colorado on the impeachment team.

Later, Ted Lieu, the California Democrat, accused Trump of lacking contrition after the riot, pointing to the former president’s claim that his speech was “appropriate”, his failure to pay his respects to a slain Capitol police officer, and the fact that it took him three days to lower the flags at the White House and other federal buildings as a mark of respect.

“It doesn’t take a prosecutor to understand that president Trump wasn’t showing remorse. He was showing defiance,” Lieu said.

He added: “He was telling us . . . that he could do this again, that he and future presidents can run for national elections, lose the election, inflame the supporters for months and then incite an insurrection.”

The prosecution also noted that Trump’s failure to sufficiently condemn the rioters had inspired domestic terrorists and far-right extremists across the country, leading to threats of further attacks in state capitols and in Washington ahead of inauguration day.

The transfer of power to Joe Biden, Trump’s successor in the White House, was protected on January 20 by the deployment of tens of thousands of National Guard troops to Washington.

On Thursday morning Biden said the powerful images and footage in the trial might have prompted some Republicans to reconsider whether to convict Trump.

“I think the Senate has a very important job to complete and I think my guess is some minds may be changed, but I don’t know.”

Biden has avoided any extensive commentary on the Senate proceedings against Trump, as he attempts to marshal Congress towards approving his $1.9tn relief package and confirming his cabinet nominees.

“I’m focused on my job . . . to deal with the promises I made,” he added. “And we all know we have to move on.”