Mr Breyer told CNN that the wife of Justice Clarence Thomas can make her own decisions about her political activity and whether it could impact the nation’s highest court – as he insisted that he “likes” both her and his conservative counterpart.
“I don’t go through that in that I strongly believe that women who are wives, including wives of Supreme Court justices, have to make the decisions about how to lead their lives, careers, what kind of career, etc., for themselves,” he said.
“I’m not going to criticise Ginni Thomas, whom I like. I’m not going to criticise Clarence, whom I like. And there we are.”
His comments come just days after it emerged that Ms Thomas had agreed to sit down for a voluntary interview with the House select committee investigating the January 6 riot at the US Capitol.
Her attorney Mark Paoletta announced this week that the conservative activist and Donald Trump supporter was “eager to answer the committee’s questions to clear up any misconceptions about her work relating to the 2020 election”.
The couple have been at the centre of controversy in recent months as details emerged about her involvement in Mr Trump’s attempts to overturn the election which President Joe Biden won.
Text messages between Ms Thomas and then-White House chief of staff Mark Meadows revealed that she repeatedly pushed false claims that the election was stolen from Mr Trump and urged the aide to help overturn the result.
“Help This Great President stand firm Mark!!! ...,” she wrote in one text message.
“You are the leader, with him, who is standing for America’s constitutional governance at the precipice.
“The majority knows Biden and the Left is attempting the greatest Heist of our History.”
Ms Thomas also contacted GOP lawmakers in Arizona and Wisconsin – key swing states won by Mr Biden in 2020 – urging them to reject the legitimate election results, according to emails.
She was also allegedly involved in Mr Trump’s “fake electors” scheme, where he is accused of trying to fraudulently appoint officials to cast votes in the Electoral College for him instead of the president the American people had chosen.
The revelations about Ms Thomas’s potential involvement in the attempts to overturn the election – which led to the insurrection on the Capitol riot – has raised major concerns about Justice Thomas’s standing on the court.
Calls have been mounting for the conservative justice to be impeached – or at the least to recuse himself from any cases related to the Capitol riot.
Mr Breyer’s diplomatic response about the Thomases came as he sat down with CNN’s Chris Wallace on Friday in his first interview since retiring from the bench.
In the wide-ranging interview, the liberal spoke of his regret that Roe v Wadewas overturned and revealed that the court was no closer to finding the source of the leaked draft opinion of the ruling.
Mr Breyer said he was “very, very, very sorry” about the court’s landmark ruling that had wiped out abortion rights across America.
"Was I happy about it? Not for an instant. Did I do everything I could to persuade people? Of course, of course,” he said.
Mr Breyer and the other liberal justices were outnumbered by Justice Thomas and the other conservative justices on the issue. Justice Thomas, the most conservative on the conservative-heavy court, has indicated he wants to go after the same-sex marriage law now that national abortion protections have been wiped out.
The ruling, scrapping half a century of legal precedent, first came to light when a draft opinion was leaked in early May.
The leak – which was unprecedented in the history of the court – is under investigation.
Mr Breyer said on Friday that the leak “was very damaging”.
“It was very damaging because that kind of thing just doesn’t happen. It just doesn’t happen. And there we are,” he said.
The former justice said that he didn’t think the source of the leak had yet been discovered.
The interview is to air Sunday on CNN’s Who’s Talking to Chris Wallace?