Trump's decision not to divest from his business interests could end up coming back to haunt him.

As the Russia probe remains in the spotlight and the Stormy Daniels case makes national headlines, there’s a third legal battle looming that could soon make Trump regret his decision not to divest from his business interests.

In a case that threatens to tear down the carefully constructed wall of secrecy surrounding Trump’s finances, the attorneys general representing the District of Columbia and Maryland are suing Trump for allegedly violating the Constitution’s emoluments clause by using his business to accept gifts (“emoluments”) from foreign or state governments.

The lawsuit cleared a critical hurdle this week, when a federal judge ruled that the case can proceed — marking the first time a lawsuit of this kind has moved past the initial stage. The ruling holds that the plaintiffs have legal standing to sue the president, and opens the door “for the plaintiffs to seek at least a portion of Trump’s tax returns,” the Washington Post reported.

“I think under pretty much any reading of the judge’s order, we can get discovery of his personal financial information in that it relates to payments from foreign and domestic governments,” Maryland Attorney General Brian E. Frosh told the Post.

Frosh said he and D.C. Attorney General Karl A. Racine also plan to seek other documents, including information related to Trump’s D.C. hotel. Since Trump took office, ethics watchdogs and national security experts have expressed concern that the property could become a conduit for governments officials from the U.S. and abroad to curry favor with Trump by spending money at his hotel.

Despite claiming that he would divest from his businesses, Trump simply turned them over to his sons — keeping himself closely involved with the company’s operations and financial dealings. The decision not to divest made Trump the first president in 40 years to maintain ownership of a private business during the presidency.

The move has allowed Trump to continue profiting from the Trump Organization while serving as president. But according to the Post, the financial arrangement has also left Trump uniquely vulnerable as three different legal teams seek to “pry open the Trump Organization’s books.”

“Now, what initially seemed like a plum arrangement for Trump — enjoying the fruits of his business while running the country — may come back to harm the Trump Organization if it is forced to reveal the kind of financial information and private correspondence that real estate firms closely guard,” the Post noted.

Trump has been notoriously secretive about his financial history, refusing to release his tax returns and saying that Mueller would be crossing a red line if he tries to look into his previous business dealings, loans, or other financial history as part of the Russia probe.

Now, as Trump stares down three separate legal teams with three different missions, his financial history is coming under an unprecedented degree of scrutiny. And as lawyers try to pry open the vault into his past, it’s his very own greed that may end up providing the key.