The retirement of a federal appeals court judge is normally not a huge national news story, and while the fact that Maryanne Trump Barry is the sister of the president of the United States makes her decision a bit more noteworthy, on its face, you can still see why it’s been treated as relatively minor news.

But peer a little bit deeper and the reason Barry is stepping down makes it clear that the story is a very big deal indeed.

The key is that last fall, the New York Times published a bombshell investigation of Donald and Maryanne Trump’s father Fred Trump’s finances that appeared to reveal, among other things, that he illegally evaded taxes in transferring much of his wealth to his children — including both Donald and Maryanne.

All this happened a long time ago, and the statute of limitations would have expired on any possible crimes. But some shrewd people noted that there is no statute of limitations on judicial ethics investigations and filed a complaint against not Donald Trump but Maryanne. This would have launched an investigation of her that would, were she found guilty of wrongdoing, have implicated the president as well.

Now, according to Russ Buettner and Susan Craig of the New York Times, Barry has retired, which renders the investigation moot. Their reporting indicates that this all actually happened in February. The complaint was filed in October, and then on February 1, a court official notified the people who filed the complaint that it was “receiving the full attention” of investigators. Ten days later, Barry filed her paperwork to resign.

And it certainly raises questions of whether she and her brother might have something to hide.

The Trump family’s shady schemes

A lot of what the Trump family did to pass on wealth tax-free to the next generations falls pretty clearly under the heading of “the real scandal is what’s legal.” But some of the Trump family shenanigans uncovered by the Times have a look of actual criminality to them.

The most striking of these, to my eye, began in 1992. The Trump kids, including Donald and Maryanne, were set up as the owners of a company called All County Building Supply & Maintenance. All County then sold boilers, refrigerators, cleaning supplies, and other equipment at unusually high prices to buildings owned by Fred Trump. On its face, this looks a lot like an illegal effort to evade gift and estate tax by masking it as a business transaction. What’s more, Fred Trump then compounded the offense because the buildings in question were rent-regulated and he cited the high prices paid as legal justification for rent increases.

This is one of several schemes the court ethics panel was in a position to look at, but now the investigation is off.

There’s a big political fight over Trump’s tax returns

This all makes for extremely relevant context as the Trump administration continues to defy legally valid requests from congressional Democrats to see his tax returns.

There has been, for years, considerable speculation around what Trump might be hiding in those returns. Guesses range from fairly wild conspiracy theories that link the tax questions to the Russia investigation and other dark plots to the apparent GOP consensus that Trump is just being touchy about something basically innocuous, like he’s maybe not as rich as he says or that, thanks to loopholes, he pays a very low effective rate.

But a possibility raised by the Times’s examination of Fred Trump’s returns is that examining his son’s returns would, likewise, reveal tax evasion.

Fred Trump evidently managed to slip these shenanigans past the investigators at the IRS, and in more recent years, the IRS enforcement budget has been cut to the bone. It makes a lot of sense for a wealthy and unscrupulous person to take a calculated risk and just break the rules. But if those returns were to be disclosed today, they would obviously attract a ton of attention from the media and various outside experts, and Maryanne Trump wouldn’t be able to avoid accountability by quietly retiring.