Donald Trump’s second impeachment trial started on Tuesday with extensive video footage of the deadly January 6 siege on the US Capitol, as Democrats made the case that the former president should be convicted for inciting an insurrection.

Jamie Raskin, the Democratic congressman from Maryland who is the lead impeachment manager and de facto chief prosecutor, played the often graphic video at the start of four hours of debate over whether it is constitutional to put a former president on trial in the Senate.

The video was a compilation of clips, played in chronological order, of the attack as seen from outside and inside the Capitol, including a snippet of Trump encouraging the crowds to “fight like hell” and march on the legislature.

The crowd subsequently staged a riot that interrupted the certification of Joe Biden’s election victory while leaving five people dead, including a Capitol police officer.

“That’s a high crime and misdemeanour,” Raskin said after showing the video. “If that’s not an impeachable offence, then there’s no such thing.”

House Democrats are hoping that Trump — who is the first president to be impeached twice — will be convicted at the conclusion of the Senate trial and subsequently barred from running for office again. But they are unlikely to secure enough votes from Republican senators to succeed.

Trump’s lawyers will argue that the former president cannot be tried as he is no longer in the White House, and that the process is therefore unconstitutional.

Raskin on Tuesday said Trump’s lawyers were trying to carve out a “January exception” for an outgoing president to be free to act as he pleases at the end of his tenure.

“Their argument is that [if] you commit an impeachable offence in your last few weeks in office, you do it with constitutional impunity. You get away with it,” Raskin said.

Raskin said that the Republicans were essentially arguing that a high crime or misdemeanour should be punished during the “vast majority” of someone’s presidency, but then “you can suddenly do it in your last few weeks of office without any constitutional accountability at all”.

Trump was impeached by the House of Representatives last month in a vote that saw 10 Republicans side with Democrats. In addition to becoming the first president to be impeached twice, he is also the first to be tried after leaving office.

Last month all but five of the 50 Senate Republicans backed a motion questioning whether the trial was constitutional, in a vote that gave tacit backing to the argument of Trump’s legal team, who say the Senate cannot try a former president.

But more than 150 legal scholars, including the co-founder and several members of the conservative Federalist Society, asserted in an open letter last month that the US constitution “permits the impeachment, conviction and disqualification of former officers, including presidents”.

The Senate’s jurisdiction in the matter will almost certainly be upheld in a simple majority vote late on Tuesday, given the upper chamber of Congress is split 50-50 between Democrats and Republicans, with Kamala Harris, the US vice-president, able to cast a tiebreaking vote.

The trial will shift on Wednesday to opening arguments from the House impeachment managers.

The process comes just a year after Trump was exonerated in another Senate trial. He was impeached in late 2019 over his efforts to get the Ukrainian president to dig up dirt on Biden and his family. Just one Republican — Mitt Romney of Utah — voted to convict in that trial.

Trump is again likely to be exonerated, as conviction requires the support of two-thirds of the chamber, or 17 Republicans given the current balance of power, assuming all 100 senators vote.

The rules for the trial were set out on Monday by Chuck Schumer, the Senate’s top Democrat, after he reached a deal with his Republican counterpart, Mitch McConnell.