The legal standard for conflicts of interest is either a direct conflict with one of the parties or the appearance of a conflict whether one exists or not, so as not to impugn the integrity of the judicial system.
Justice Thomas went “large” on a private yacht vacation in 2019, in a trip with travel expenses of about $500K had he paid them himself but, ah, he didn’t. From Pro Publica:
In late June 2019, right after the U.S. Supreme Court released its final opinion of the term, Justice Clarence Thomas boarded a large private jet headed to Indonesia. He and his wife were going on vacation: nine days of island-hopping in a volcanic archipelago on a superyacht staffed by a coterie of attendants and a private chef.
If Thomas had chartered the plane and the 162-foot yacht himself, the total cost of the trip could have exceeded $500,000. Fortunately for him, that wasn’t necessary: He was on vacation with real estate magnate and Republican megadonor Harlan Crow, who owned the jet — and the yacht, too.
For more than two decades, Thomas has accepted luxury trips virtually every year from the Dallas businessman without disclosing them, documents and interviews show. A public servant who has a salary of $285,000, he has vacationed on Crow’s superyacht around the globe. He flies on Crow’s Bombardier Global 5000 jet.
And obviously, you see the problem. A Republican megadonor has no business paying the entire cost of a justice’s vacation. This would have been automatic impeachment just 25-30 years ago before the Koch brothers started inviting Alito and that Thomas guy to symposiums (Koch Konservative symposiums). That turned on the tap.
Other justices do cool things that are paid for, Justice Roberts, another conservative, has honestly and appropriately attended law symposiums around the world and has been paid a significant speaking feel (as well as travel and accommodations) but that is expected of a Justice and it has no indicia of any sort of conflict of interest, nor even an appearance. He teaches and being the SCOTUS Chief, he commands a high price.
Liberal Justices are not immune. They have attended events here in the United States (Akin to Amy Coney-Barrett) that in a perfect world, they wouldn’t attend. But as always, Thomas is at a completely different level. He must feel a bit like Trump in a sense. His wife can be texting the President’s Chief of Staff and Thomas says he doesn’t know a thing about it. And people walk around as if this is normal or real.