Donald Trump’s legal team on Friday accused Democrats of a launching “campaign of retribution” against the former US president, as his Senate impeachment trial for inciting an insurrection entered its final stretch.

Michael Van Der Veen, one of Trump’s attorneys, called the article of impeachment an “unjust and blatantly unconstitutional act of political vengeance”, before playing a tape of Democratic lawmakers calling for his client’s impeachment as far back as early 2017.

Trump’s lawyers are expected to take just a few hours to defend their client, who was last month impeached by the House of Representatives on one charge of inciting an insurrection for his role in the January 6 attack on the US Capitol that left five people dead.

Trump’s legal team is entitled to up to two days to make its presentation to senators, who are acting as jurors in the impeachment trial.

But trial lawyer David Schoen told reporters on Capitol Hill late on Thursday that the legal team would take “maybe three to four hours” to argue Trump’s speech was protected under the First Amendment of the US Constitution. Trump’s legal team has also repeatedly argued the Senate does not have jurisdiction to try a former president.

Schoen and Bruce Castor Jr, a former prosecutor from Pennsylvania, were widely criticised this week for their performance in a debate on the constitutionality of the trial. One Republican senator, Bill Cassidy of Louisiana, responded to their arguments by voting with Democrats. “As an impartial juror, I’m going to vote for the side that did the good job,” he said.

Trump’s lawyers met on Thursday with a small group of GOP senators who are among the former president’s most ardent defenders, including Lindsey Graham of South Carolina and Ted Cruz of Texas. The move attracted criticism given senators swore an oath to act as impartial jurors in the trial.

Cruz told reporters after the meeting that senators shared their “thoughts” on the team’s legal strategy.

“I think the end result of this impeachment trial is crystal clear to everybody,” he added. “Donald Trump will be acquitted, and every person in the Senate chamber understands there are not the votes to convict him.”

Friday’s presentation will come after two days of arguments from House Democrats, who are acting as prosecutors in the case. Led by Jamie Raskin, a Democratic congressman from Delaware, their presentation included hundreds of Twitter messages, videos and speeches from the former president, as well as previously unseen security camera footage from inside the Capitol during the riot.

Several Republican senators praised the Democrats’ presentation. But a critical mass of Republicans is unlikely to vote to convict Trump, or bar him from holding future office, with a majority of them previously voting that the trial is not constitutional.

Under the constitution, two-thirds of the US Senate would need to find Trump guilty in order for him to be convicted — something that would require the support of 17 Republican lawmakers given the upper chamber of Congress is currently split, 50-50, between Republicans and Democrats. Trump could then be banned from holding future office with a simple majority vote.

Joe Biden told reporters at the White House on Friday morning that he was “anxious” to see how Republicans voted in the trial.

“I’m just anxious to see what my Republican friends do, if they stand up,” he said. Biden, who was sworn in as president on January 20, spent several decades in the Senate before serving as Barack Obama’s vice-president.

Last month, more than 150 legal scholars, including the founder of the conservative legal group the Federalist Society and several members, wrote an open letter arguing the constitution allowed for the trials of both current and former public officials.

Trump’s impeachment trial has exposed long-simmering tensions within the Republican party and underscored the grip the former president retains on the party’s voters and elected lawmakers.

In an interview published on Friday in Politico Magazine, Nikki Haley, the former Republican governor of South Carolina who is widely seen as a potential candidate for president in 2024, said impeachment proceedings were a “waste of time” but insisted Trump would not be running for office again.

“I don’t think he’s going to be in the picture,” she said in the interview, which was conducted on January 12, one day before Trump was impeached by the House. “I don’t think he can. He’s fallen so far.”