The January 6 committee assumes the former vice-president Mike Pence will testify before it, a panel member said on Sunday.

“I would assume he is going to come forward and testify voluntarily,” Jamie Raskin, a Democratic congressman from Maryland, told CBS’s Face the Nation.

Raskin also said Ginni Thomas, a rightwing activist married to the supreme court justice Clarence Thomas, “has relevant testimony to render [and] should come forward and give it”.

After the 2020 election, Ginni Thomas contacted Republicans in Arizona and Wisconsin, pushing them to overturn Joe Biden’s victories in the key swing states.

Members of the January 6 committee including Liz Cheney, the vice-chair and one of two Republicans on the panel, have said Thomas could face a subpoena. But none has been forthcoming.

Clarence Thomas was the only justice to say Donald Trump should not have to surrender records to the committee as it investigates Trump’s attempt to overturn his 2020 defeat and the deadly attack on Congress it inspired.

It subsequently emerged that Ginni Thomas was in contact with the Trump White House as it attempted to nullify electoral results in key states.

Pence presided over the certification of electoral college results at the Capitol on 6 January 2021, which the mob Trump told to “fight like hell” was attempting to stop.

Pence refused to stop certification, as advisers to Trump claimed he could. Some rioters chanted “Hang Mike Pence” and erected a gallows. The vice-president narrowly escaped contact with some who breached the Capitol.

In testimony to the January 6 committee, Cassidy Hutchinson, a former White House staffer, said Trump told senior aides Pence “deserved” such treatment.

Sticking to his lie that Biden’s win was the result of electoral fraud, Trump said this week the 2020 election should be re-run.

Raskin – a professor of constitutional law – told CBS: “Well, first, if he’s saying that the election should be rerun, which is something he’s been saying from the beginning, that’s totally outside of the constitution.

“There is no procedure for the military just to seize the election machinery and run a new election, which is one of the things that [Trump’s] disgraced former national security adviser Michael Flynn was pushing and we know was part of the January 6 plot.

“And look, more than 60 courts rejected every claim of electoral fraud and corruption which Donald Trump advanced. He’s had the benefit of more than 60 courts, including eight courts where he appointed the judges to office, look[ing] at all those claims, and they were all rejected. It was rejected in the states and he lost the election.”

Raskin was also asked about Republican anger over Biden’s primetime address in Philadelphia on Thursday, in which the president warned that Trump and his supporters posed a threat to American democracy.

Raskin said: “Two of the hallmarks of a fascist political party are one, they don’t accept the results of elections that don’t go their way, and two, they embrace political violence.

“And I think that’s why President Biden was right to sound the alarm this week about these continuing attacks on our constitutional order from the outside by Donald Trump and his movement.”