WASHINGTON — Whenever allegations of ethical lapses are made in the Supreme Court, the same question is asked: Why, unlike federal judges in the lower courts, don’t the nine justices have a binding code of conduct?

It arose amid furor over the conservative political activism of Judge Clarence Thomas’ wife, Virginia «Ginni» Thomas, including her support for former President Donald Trump’s efforts to overturn the 2020 election results.

It arose when conservative Justice Antonin Scalia was duck hunting with then Vice President Dick Cheney when Cheney was involved in a pending court case.

It arose when liberal Justice Ruth Bader Ginsburg harshly criticized then-Republican presidential candidate Trump during the 2016 election.

And it came up last week with questions raised about the legal recruiting work done by the wife of Chief Justice John Roberts, Jane Roberts, in which she has worked with law firms that have cases before the court.

So far, the judges have stood their ground, even though district court and appellate court judges are bound by a judicial code of ethics. Among other things, it requires judges to «avoid impropriety and the appearance of impropriety in all activities.» If judges break the code, they can be investigated and reprimanded through a separate complaints process.

The judges say they follow the spirit of the code, introduced in 1973, but have never formally adopted one of their own. Nor is there a procedure that allows complaints to be investigated except for the drastic step of impeachment.

The pressure has repeatedly come from Congress, with Sen. Chris Murphy, D-Conn., set to reintroduce legislation on Thursday that would require judges to adopt a code. Similar efforts in recent years have failed.

“It is a simple, nonpartisan solution to increase transparency, enforce accountability and begin to rebuild public trust in the court,” Murphy said in a statement.

The bill, like previous versions, would task the Judicial Conference of the United States, the policy-making body for federal courts, with issuing within a year of enactment a code of conduct applicable to judges of the Supreme Court. It also contains a new provision that would authorize an ethics investigation attorney who would have the power to enforce the code.

Murphy has more than 20 cosponsors in the Senate, and Rep. Hank Johnson, D-Ga, will introduce companion legislation in the House of Representatives.

The Senate Judiciary Committee is expected to hold a hearing on judicial ethics, a Senate Democratic aide said.

Earlier this week, the American Bar Association, a national group representing lawyers, also called that judges adopt a code of ethics.

Roberts addressed the court’s inaction on the issue in his 2011 year-end statement. report on the judiciary, saying it was a «misconception» that the Supreme Court has laxer ethical standards than lower courts.

«All members of the court, in fact, refer to the code of conduct when assessing their ethical obligations,» he said.

Any effort by Congress to intervene could raise constitutional questions because lawmakers would be meddling in the internal affairs of a separate branch of government. But the Supreme Court already follows the impeachment and financial disclosure rules that were adopted by Congress. The court, as Roberts noted in 2011, «has never addressed whether Congress can impose those requirements.»

Supreme Court spokeswoman Patricia McCabe declined to comment.

Judicial reform used to be a bipartisan issue, but in recent years, with increasing scrutiny, especially on the left, of conservative justices, including not only Thomas but also Justice Brett Kavanaugh after his controversial Senate confirmation, Republicans have become less likely to back legislative efforts. This has also coincided with the court’s swing to the right, thanks to a 6-3 conservative majority made possible by all three of Trump’s appointments.

In the wake of calls last year for Thomas to refrain from cases involving Trump because of his wife’s involvement in efforts to overturn the 2020 election, Senate Republican leader Mitch McConnell combined several problems, characterizing the Democratic calls for reform as «part of a years-long quest to delegitimize the court.» He dismissed the Democratic concerns as «spurious allegations about false ethics issues or bias.»

Gabe Roth, executive director of Fix the Court, a nonpartisan court reform group, said he is trying to convince Republicans that the ethics rules aren’t just aimed at conservatives.

«That’s the way it gets covered, unfortunately, in the conservative media,» he said.

If the Supreme Court were to voluntarily adopt a code of conduct, the first of what Roth hopes will be a whole series of reforms, «it would be an easy victory» for justices, he added.

Ethicists have long pressed judges to take that step.

Their failure to do so «makes it seem like they have something to hide,» said Arthur Hellman, a professor at the University of Pittsburgh School of Law.

But Charles Geyh, a professor at Indiana University Maurer School of Law, noted that the court traditionally gets angry when Congress gives orders.

«In a less tense political environment, this standoff could and should be ended by congressional leaders quietly consulting with members of the court and agreeing to stand down if the court takes on the task of adopting a code,» he said.