That actually sounds a lot like the Crow-Thomas relationship. But the court held that such an arrangement is not unlawful. The gratuities law, the court ruled, requires that a particular gift be linked to a particular official act. Without such a direct link, a series of gifts to a public official over time does not violate the statute, even if the goal is to curry favor with an official who could act to benefit the gift giver.

In the wake of Sun-Diamond, federal prosecutors increasingly turned to a more expansive legal theory known as honest services fraud. But in Skilling v. United States, the court ruled that theory is limited to cases of bribes and kickbacks — once again, direct quid pro quo deals. Three justices, including Justice Thomas, wanted to go even further and declare the statute that prohibits honest services fraud unconstitutional.

The court proceeded to limit its “crabbed view of corruption” even further. In the 2016 case McDonnell v. United States, the court held that selling government access is not unlawful. Gov. Bob McDonnell of Virginia and his wife, Maureen, accepted about $175,000 in secret gifts from the businessman Jonnie Williams, who wanted Virginia’s public universities to perform research studies on his company’s dietary supplement to assist with its F.D.A. approval. In exchange, Mr. McDonnell asked subordinates to meet with Mr. Williams about such studies and hosted a luncheon at the governor’s mansion to connect him with university health researchers.

A jury convicted the McDonnells on several counts of corruption. The U.S. Court of Appeals for the Fourth Circuit — hardly known as a bastion of liberalism — unanimously affirmed the convictions. But the Supreme Court unanimously reversed, holding that the things Mr. McDonnell did for Mr. Williams did not qualify as “official acts” under federal bribery law. Selling official access may be tawdry, the court held, but it is not a crime.

Those who think Justice Thomas may be guilty of corruption may not realize just how difficult the court itself has made it to prove such a case. Now only the most ham-handed officials, clumsy enough to engage in a direct quid pro quo, risk prosecution.

Viewed in light of this history, the Thomas scandal becomes less surprising. Its own rulings would indicate that the Supreme Court doesn’t believe what he did is corrupt. A powerful conservative with interests before the court who regularly provides a justice with vacations worth more than his annual salary is, as the court said in Citizens United, merely the “appearance” of potential corruption. In the court’s view, the public has no reason to be concerned.

But the public clearly is, and should be, concerned over the ability of the rich and powerful to purchase access and influence unavailable to most citizens. Unfortunately, Citizens United is here to stay without a constitutional amendment or an overruling by the court, neither of which is very likely.