Updated April 18, 2023 at 9:49 AM ET

For years, as members of Congress and people in the executive branch suffered through embarrassing headlines about ethics lapses, the U.S. Supreme Court seemed to occupy something of a moral high ground. But a bombshell report from ProPublica this month may have changed that. Reporters with ProPublica documented a long relationship between Thomas and Republican donor Harlan Crow, in which the billionaire showered Thomas and his wife with luxury vacations for more than 20 years.

The Senate Judiciary Committee - which is controlled by Democrats - plans to hold a hearing on the Supreme Court's ethical standards, and may even call Justice Thomas to appear. After a meeting of Democrats on the committee Monday night, Committee member Sen. Richard Blumenthal (D-Conn), who has been searing in his criticism of Justice Thomas, said he hoped Justice Thomas would appear voluntarily.

The headlines about Justice Thomas keep coming. This week, the Washington Post reported that Thomas continued to claim annual rental income from a real estate firm that ceased to exist in 2006.

"Taken together with other errors and omissions on his financial disclosure forms over the years, it's part of a pattern that has raised questions about how seriously he views his responsibility to accurately report details of his finances to the public," Post reporter Emma Brown told NPR's Leila Fadel on Morning Edition.

Thomas has not responded to the Post report on the real estate earnings. He defended the non-disclosure of Crow's gifts in a statement, saying he'd been advised that gifts from a friend who had no business before the court were not reportable.

But some ethics lawyers reject that. NPR's Michel Martin spoke to two experts: Virginia Canter, chief ethics counsel at Citizens for Responsibility and Ethics in Washington, and Julian Zelizer, a professor of history and public affairs at Princeton University.

This interview has been lightly edited for length and clarity.

Interview highlights

On whether Justice Thomas abused his office

Virginia Canter

It's our nation's highest court. And the fact that he was accepting – repeatedly – private plane trips, yacht cruises, luxury resort vacations, without disclosing them, indicates he was in violation of the Ethics in Government Act, which was an act passed by Congress after Watergate.

The only exception for reporting gifts from friends is something called the personal hospitality exception, and it only applies to food, lodging and entertainment. It does not at all apply to transportation. They can only be accepted from someone with whom he had a personal relationship, and that it was a reciprocal relationship. In other words, as a friend, I invite you over to dinner and you invite me over to dinner. That's reciprocity. But there's no way Justice Thomas and his wife could ever afford these types of gifts, let alone reciprocate them. The fact that they met after he took office completely undermines the argument that it was a pre-existing personal relationship.

On the existing ethics standards for the Supreme Court

Virginia Canter

On the lower court, federal judges are subject to a misconduct review that would be carried out through a very detailed process. However, there's no similar type of accountability at this time for any member of the Supreme Court, which is why there has been such a strong push by members of Congress for the Supreme Court to adopt a code of conduct that would establish a framework for addressing and investigating misconduct.

Julian Zelizer

There's different modes of enforcement. Obviously, the court could police itself. There could be some kind of internal mechanism of investigation, which can happen already. And ideally, that is the best way for the court to handle this. But the other avenue would be legislating this problem. I don't know what kind of mechanism you can set up, but it would be externally put into place rather than just depending on the Chief Justice to do this on their own.

On whether ethics questions undermine the Supreme Court's authority

Julian Zelizer

The stories that now surround Justice Thomas are bringing immense questions, not just about him, but about how the Court operates. How do we police what justices do and cannot do, and can we have confidence that justices in the highest court of the land are making decisions based on their interpretation of the law rather than their political preferences? I think we're at one of these important, pivotal turning points when the Court has to decide what it's going to do, if anything. And if the court isn't going to do something, will Congress perhaps step in?

On whether the ethics issue rises above politics

Virginia Canter

I think the American people intuitively understand when officials are potentially engaged in corrupt activity. They have a visceral reaction to it, there is a line that cannot be crossed, and I think this is probably one of them. By accepting these gifts, the Justice has completely undermined the public's trust in the ability of the court to faithfully and impartially discharge their obligations, to apply equal justice under law. The problem here is you really can't put the genie back in the bottle. You can't just have him say, 'I'll go back and report these gifts.' I'm not sure how we restore the integrity of the court after these events have occurred.

Julian Zelizer

We've had moments where the American public can look at behavior that's happened in the past, when it actually shakes some of the partisan status quo and leads to a push for some kind of reform. We just had passage, for example, of a reform of the Electoral College system. It was a moderate reform, but it was in the aftermath of what happened in 2020. And there's something about this story. It's so personal, it's so vivid. It could give some fuel to public support for institutional reforms. I think many Americans, including many independents, will understand this is not right for the Court, for the system. And that's how you can get a moment when you can break through an unwillingness to change how institutions work.

Jan Johnson and Miranda Kennedy edited this story. Ben Abrams produced the audio version. contributed to this story

Copyright 2023 NPR. To see more, visit https://www.npr.org.