The conservative activist Ginni Thomas has “no memory” of what she discussed with her husband, the supreme court justice Clarence Thomas, during the heat of the battle to overturn the 2020 presidential election, according to congressional testimony released on Friday.

Thomas, 65, recalled “an emotional time” in which her mood was lifted by her husband and Mark Meadows, then Donald Trump’s chief of staff, a transcript of her deposition with the congressional committee investigating the January 6 attack on the US Capitol showed.

Thomas has been a prominent backer of Trump’s lies that the 2020 presidential election was stolen from him.

At 74, her husband is the oldest and most conservative member of America’s highest court, which has played a crucial part in settling disputed elections.

The January 6 committee spent months seeking an interview with Ginni Thomas, who was known to have texted Meadows and contacted officials in Arizona and Wisconsin in the aftermath of Trump’s election defeat by Joe Biden. She was eventually interviewed behind closed doors on 29 September.

In opening remarks, Thomas said she entered Republican politics long before meeting Clarence Thomas in 1986. She said her husband had never spoken to her about court cases – “it’s an ironclad rule in our house” – and was “uninterested in politics”.

She added: “I am certain I never spoke with him about any of the challenges to the 2020 election, as I was not involved in those challenges in any way.”

Thomas also claimed the justice was unaware of texts she exchanged with Meadows and took a swipe at the committee for having “leaked them to the press while my husband was in a hospital bed fighting an infection”.

She scorned the idea that she could influence the legal decisions of her “independent and stubborn” spouse.

But during cross-examination by committee members, Thomas was confronted with the texts she sent to Meadows as Trump baselessly challenged his election defeat.

On 24 November 2020, Thomas wrote: “I can’t see Americans swallowing the obvious fraud. Just going with one more thing with no frickin’ consequences, the whole coup, and now this.”

Meadows responded: “This is a fight of good versus evil. Evil always looks like the victor until the King of Kings triumphs. Do not grow weary in well doing. The fight continues. I have staked my career on it. Well at least my time in DC on it.”

Thomas wrote back a few minutes later: “Thank you. Needed that, this plus a conversation with my best friend just now. I will try to keep holding on.”

The committee probed whom she meant by “best friend”.

Thomas admitted: “It looks like my husband.”

Asked if she remembered what she and Clarence Thomas talked about that made her feel better, Thomas replied: “I wish I could remember but I have no memory of the specifics. My husband often administers spousal support to the wife that’s upset. So I assume that’s what it was. I don’t have a specific memory of it.”

Thomas denied having any conversations with Clarence Thomas about the fact she was in contact with Meadows in the post-election period.

“He found out in March of this year when it hit the newspapers,” she said, reiterating that her husband “is not interested in politics”.

Thomas refused to back down from her view that widespread election fraud took place but declined to offer specific evidence. She admitted she had been “frustrated” that Trump’s vice-president, Mike Pence, did not talk more about “irregularities” in certain states.

But having initially expressed hope that lawyer Sidney Powell could overturn the election – “Release the Kraken and save us from the left taking America down,” she wrote – Thomas said Meadows “corrected” her view of the discredited attorney.

Thomas told the committee: “I worried that there was fraud and irregularities that distorted the election but it wasn’t uncovered in a timely manner, so we have President Biden.”

Regarding her texts with Meadows, she explained that “it was an emotional time” and she is “sorry these texts exist”.

She added: “I regret all of these texts.”

Critics have argued that given Thomas’s political activities and contacts with Meadows and other key Trump allies, Clarence Thomas should have recused himself from any case linked to the insurrection.

The January 6 committee report, published last week, ran to 845 pages but made no reference to Ginni Thomas.