(CNN) — Amid calls for Justice Clarence Thomas to recuse himself from a high-stakes case over whether Donald Trump has presidential immunity from criminal prosecution, the conservative jurist has made clear that he doesn’t plan to step aside – or even respond publicly to the appeals from Democrats and others.

The justice’s critics are all citing past efforts by his wife, Virginia “Ginni” Thomas, to reverse the 2020 presidential election in Trump’s favor and her attendance at the rally Trump held on January 6, 2021, shortly before the US Capitol attack.

Thus far, Thomas has given no sign that he intends to recuse himself from Trump v. US – or even explain his reasoning for remaining on the case, which the nine justices will hear arguments in on Thursday.

Judicial ethics experts say that Thomas at least has an obligation to explain his decision not to recuse himself given the precedent set by other justices in the past.

“Reasonable people are questioning Justice Thomas’ partiality and I think I think he definitely owes the American people an explanation of why he is unbiased in these cases,” said Gabe Roth, executive director of Fix the Court, which has pushed for more transparency from the federal judiciary.

“I think that’s a fairly low bar,” Roth added. “You think you’re unbiased, OK, tell us why.”

The court has not responded to CNN’s requests for comment.

Supreme Court justices have carte blanche over recusal decisions. The nine adhere to a code of conduct released by the court last year in response to a series of ethics controversies, and they also follow the code enforced against lower-court judges and comply with federal law governing certain judicial conduct, including recusals.

The code says in part that a justice should recuse themselves “in a proceeding in which the Justice’s impartiality might reasonably be questioned, that is, where an unbiased and reasonable person who is aware of all relevant circumstances would doubt that the Justice could fairly discharge his or her duties.”

But the various recusal rules leave the final decision to the justice, with no formal way for the chief justice or other members of the court to play any role in their colleague’s choice.

‘No one will hold him accountable’

Those calling on Thomas to recuse himself from Thursday’s case are pointing to a series of actions by his wife related to the 2020 election that have been extensively reported on by CNN and other outlets.

“He’s still never answered questions about what he knew about his wife’s insurrectionist activities as he sat on cases directly involving those activities,” Rhode Island Democratic Sen. Sheldon Whitehouse told CNN in a statement, referring to other January 6-related cases, including one the court heard last week. Whitehouse chairs the Senate Judiciary subcommittee looking into judicial ethics.

Thomas has faced a steady stream of recusal calls since December, when special counsel Jack Smith asked the Supreme Court to hear the immunity dispute on an emergency basis.

The justices ultimately let the DC Circuit Court of Appeals hear the case first, but a separate dispute over whether Trump should be kicked off of Colorado’s 2024 ballot prompted more recusal calls, including a letter from a group of eight Democratic lawmakers to Justice Thomas that argued Ginni Thomas’ activism should disqualify her husband from participating in that matter.

Georgia Rep. Hank Johnson, who spearheaded the letter, told CNN in a statement this week that Thomas’ “refusal to recuse on matters before the court that involve his wife and their personal self-interests is deeply disturbing.”

“It further erodes public confidence and trust not just in the Supreme Court, but our very democracy,” added Johnson, the top Democrat on the House Judiciary subcommittee that oversees the federal courts. “He refuses to recuse because he knows no one will hold him accountable,”

In an interview Ginni Thomas gave two years ago, the conservative activist said that although she attended the “Stop the Steal” rally held by Trump on January 6, 2021, she “played no role” in planning the events that day and that she does not involve her husband in the political work she does.

Critics have also seized on the fact that Ginni Thomas had exchanged texts with Mark Meadows – then-President Donald Trump’s White House chief of staff – about Trump’s efforts to overturn the results. Meadows has also sought to invoke immunity in the Georgia election subversion case, an argument rebuffed by federal courts.

“Help This Great President stand firm, Mark!!! … 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,” she wrote November 10, 2020, in one such text.

In her interview two years ago, Ginni Thomas said she was “disappointed and frustrated that there was violence that happened following a peaceful gathering of Trump supporters on the Ellipse on January 6th.”

For his part, Justice Thomas has never publicly commented on his wife’s attendance at the January 6 rally or her efforts to reverse the election results.

The code adopted by the justices last year is careful to note that any recusal from a justice could be especially consequential given the fact that the justice could not be swapped out for an alternate jurist, which is possible at the lower-court level.

“The loss of even one Justice may undermine the ‘fruitful interchange of minds which is indispensable’ to the Court’s decision-making process,” the newly adopted code states.

Trump is asking the court to grant him presidential immunity from prosecution in the federal election subversion case brought against him by Smith. Lower courts sided against the former president, ruling that no such immunity exists.

If Thomas were to recuse himself from the case and the court split 4-4, that outcome would allow the historic criminal prosecution to proceed.

Recusals at the high court

Recusals at the Supreme Court are not unheard of.

Last September, Justice Samuel Alito issued a defiant explanation for why he was refusing to recuse himself from a major tax case the court would soon hear, sharply rejecting calls by some Democrats for him to step aside after he gave an interview to one of the attorneys involved in the case.

“There is no valid reason for my recusal in this case,” the conservative justice wrote in a 4-page statement responding to the appeals from Senate Judiciary Chairman Dick Durbin and others. The Illinois Democrat has also urged Thomas to step aside from the Trump cases before the court this year.

Other recusal issues are less controversial, such as when a justice steps aside from a case because they handled the matter when they were serving as a lower-court judge.

Liberal Justice Ketanji Brown Jackson recused herself from the Harvard affirmative action case the court decided last year because she had served on the school’s Board of Overseers before joining the court. (Jackson did take part in a similar case centered on the University of North Carolina that was argued and decided at the same time.)

And in 2020, the court announced that Justice Sonia Sotomayor would not take part in a case concerning so-called faithless presidential electors. The court’s clerk said at the time that the liberal justice “believes that her impartiality might reasonably be questioned” due to her friendship with one of the litigants in the case.

Thomas, too, has occasionally recused himself from a case. In one notable example last fall, he said that he did not participate in the court’s consideration of an appeal brought by former Trump attorney John Eastman in a January 6-related case. Though he did not explain the reasoning for his recusal in that matter, Eastman is one of Thomas’ former clerks.

Thomas’ recusal in that case remains the only time he sat out of a January 6 case before the high court.

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