GEOFF BENNETT: The billionaire GOP donor Harlan Crow for several years paid the pricey boarding school tuition for a grandnephew of Supreme Court Justice Clarence Thomas.

That's according to exclusive new reporting by ProPublica.

Justice Thomas never disclosed in official filings that Crow was paying tuition for the boy, who Thomas at the time was raising as his son.

Combined with ProPublica's previous reporting on Thomas and Crow, it paints a picture of a billionaire political donor providing a Supreme Court justice with lavish vacations and purchasing a house where Thomas' mother lives, apparently rent-free.

Josh Kaplan is among the ProPublica reporters who broke this story and joins us now.

Josh, welcome back to the "NewsHour."

And we should say, this was nearly 20 years ago.

Justice Thomas says that he was raising his grandnephew as his son because the boy's father at the time was imprisoned in connection with a drug case.

Walk us through your reporting about this tuition arrangement and Justice Thomas' failure to disclose it.

JOSHUA KAPLAN, ProPublica: Yes, so we found that this billionaire Republican megadonor, Harlan Crow, secretly paid private school tuition for Thomas' grandnephew.

And, as you said, I mean, this was not a distant relative of Thomas'.

He was his legal guardian.

He had taken custody of him at the age of 6.

And he said in his own words that he was raising him as a son.

And then, for high schools, Thomas sent the child to private boarding school -- two private boarding schools, actually, one in Georgia, one in Virginia.

And Harlan Crow secretly footed the bill.

So, as you mentioned, we have been reporting on Crow's unusual role helping fund the life of Thomas and his family.

And this adds a whole new dimension to that.

GEOFF BENNETT: Well, there is another unusual dimension here, in that Justice Thomas did not disclose that Crow was paying for tuition, but he did disclose another much less generous payment of $5,000 by another friend that was paid toward the tuition.

It raises the question, why disclose one payment and not the other?

JOSHUA KAPLAN: Yes, we had that question too.

And we asked Thomas.

He didn't respond.

Ethics experts told us this could be seen as evidence that he understood his legal obligation to disclose such gifts.

So there's a federal law passed after Watergate that requires justices and most other officials to report most gifts to the public.

And experts told us that they believe Thomas is required by law to disclose these payments.

They said he could argue that the gifts were to the child, not to him, and so he didn't have to, but they said that was far-fetched.

Children generally don't pay their own tuition.

It's the legal guardian's responsibility to do so.

GEOFF BENNETT: Well, the Supreme Court did not immediately respond to our request for comment.

But Mr. Crow's office told your publication in part in a statement that reads this way: "Harlan Crow has long been passionate about the importance of quality education and giving back to those less fortunate, especially at-risk youth.

It's disappointing that those with partisan political interests would try to turn helping at-risk youth with tuition assistance into something nefarious or political."

Josh, he is not disputing the facts presented in the story.

JOSHUA KAPLAN: No, he's not.

And, actually, after we published this, a longtime friend of Thomas' and who's served as a lawyer for his wife released a statement also confirming the reporting and saying that Crow paid for two years of tuition, one at one school and one at the other.

Yes, I mean, I think in general, in these discussions about disclosure laws, something that can be lost is this conversation of the ethics of that sort of payment, how we should expect our public officials to conduct themselves, what gifts we think it's OK for them to accept, especially in secret.

We talked to a former White House ethics lawyer for George Bush, who said that this is way beyond anything he's ever seen.

And he said that, when he was at the White House, if an official had accepted what Thomas had, they would have been fired.

GEOFF BENNETT: Josh Kaplan, a reporter with ProPublica, thanks for sharing your reporting with us.

JOSHUA KAPLAN: Thanks so much for having me.