The House Select Committee to Investigate the January 6th Attack on the United States Capitol will in coming weeks close several circles of evidence in ways that confirm the deadly insurrection on January 6, 2021, as “the culmination of a coup attempt” carried out at the behest of former President Trump. The committee’s upcoming—and potentially final—hearing should remove any doubt that Trump must be held to account for attempting to halt the transfer of power to his legitimate successor.

But the committee cannot simply finish its business with a recommendation that Trump and his closest associates face criminal charges and civil sanctions for plotting and implementing an insurrection. The committee must also pursue—and respond to—evidence that suggests Justice Clarence Thomas abused his position to thwart investigations into a cabal of plotters that included his wife, Virginia “Ginni” Thomas.

Faced with a subpoena threat, Ginni Thomas spoke to the committee on Thursday, in a session where she echoed the “Big Lie” delusions of Trump and others who sought to overturn the results of the 2020 presidential election.

Ginni Thomas, a longtime ally and associate of extreme right-wing groups, was by all accounts a highly engaged, highly influential, and highly connected participant in the coup plot. In addition to her well-documented texting with former Trump White House chief of staff Mark Meadows about strategies for overturning Democrat Joe Biden’s Electoral College win, reports have surfaced that Ginni Thomas pressured Republicans in Arizona and Wisconsin to submit slates of fake electors for Trump. The development of these lists of fake electors from closely contested states was central to the coup plot, as the conspirators hoped Vice President Mike Pence would use them to obstruct the certification of the election. That would have thrown the contest to Congress, where Republicans had an advantage that the plotters believed would favor Trump.

Pence refused to go along with the scheme, inspiring Trump’s fury and threats by the insurrectionists to hang the vice president.

Put the pieces together and it becomes absolutely clear that Ginni Thomas’s actions must be a focus of the January 6 committee’s final deliberations. And so, too, must the actions of Clarence Thomas. As American University law professor Kimberly Wehle notes, “it’s impossible to predict where the further unraveling of the Ginni Thomas conflicts might lead—and whether those facts could produce another unprecedented fissure in our system of government. For now, Congress must, at the very least, peer behind the Thomases’ curtain.”

What committee members will find are troubling patterns that suggest Justice Thomas abused his position not once, but at least twice:

In December 2020, as part of a last-ditch effort to prevent the Electoral College from confirming Biden’s election, Texas State Attorney General Ken Paxton, a right-wing zealot closely aligned with Trump, asked the US Supreme Court to block four states—Georgia, Michigan, Pennsylvania, and Wisconsin—from casting their Electoral College votes for the president-elect. Trump sought to intervene on Paxton’s side.

In the deliberations, Trump was represented by John Eastman, a lawyer and college professor who has been identified as the architect of the plan to have Pence upend the certification of electoral votes. (Notably, references to Ginni Thomas in communications from Eastman, a former law clerk to Justice Thomas, led the January 6 committee to subpoena the justice’s wife.)

On December 11, 2020, the conservative-dominated Supreme Court rejected Paxton’s argument. Only two justices sided with Trump and the Texan: the court’s most partisan judicial activist, Samuel Alito, and Clarence Thomas.

Almost a year later, as the inquiry into all this plotting was getting going, Trump attempted to block the release of presidential records to the January 6 committee.

The January 19, 2022, decision by the Supreme Court rejected the former president’s argument. This time, even Alito sided with the rule of law. But there was one dissenter: Clarence Thomas.

Justice Thomas offered no explanation for why he supported Trump’s outlandish demand. But Representative Bill Pascrell (D-N.J.) concluded that—because the justice “heard election cases while his wife conspired to overthrow democracy”—“Clarence Thomas cannot possibly be seen as a neutral actor but instead as a corrupt jurist who has poisoned the High Court. Clarence Thomas should have dignity and final respect for our democracy and resign.” When revelations about the 29 texts Ginni Thomas sent to Meadows surfaced, Representative Jamaal Bowman (D-N.Y.) argued that Justice Thomas’s failure to recuse from cases involving the election, and investigations into the insurrection, was such a severe ethical lapse that the justice should be impeached.

The members of the January 6 committee may or may not reach the same conclusions as their House colleagues. But they have to examine these issues.

Based on what we now know about Ginni Thomas’s hectoring of Republicans in battleground states to come up with those lists of fake electors at the same time the Supreme Court was deliberating on the Electoral College question, and with what we also know about her detailed communications with the White House in the weeks leading up to the insurrection, the committee has to examine not just the actions of Ginni Thomas but also the influence they may have had on Clarence Thomas.

The committee must entertain the question of whether Clarence Thomas’s dissent in the Texas case was in any way guided by communications with his wife or others who were engaged in the conspiracy. And it must ask whether the justice’s lonely dissent in the presidential records case was motivated by a desire to hide details of inappropriate activity by his wife and her co-conspirators.

The January 6 committee is now on a fast track, as its work must be completed before the 117th Congress ends on January 3, 2023. But there is enough time to sort out the questions that veteran broadcaster Dan Rather posed when the details of Ginni Thomas’s insurrectionist interventions became evident: “What does Clarence Thomas know? And when did he know it?”