DAYS AFTER he took office, Donald Trump found himself as a defendant in a lawsuit based on the constitution's two “emoluments” clauses which prevent presidents from profiting from their office. Mr Trump dismissed the suit as “totally without merit”. In December 2017, he was vindicated in a ruling by George Daniels, a federal district judge in New York City, who determined that none of the plaintiffs pushing the suit had “standing”: the legal right to sue. But on September 13th, with two similar cases stuck in other courts, a three-judge panel of the Second Circuit Court of Appeals voted 2-1 to set aside Judge Daniels’s ruling and revive the lawsuit. Barring a contrary ruling from the full Second Circuit or emergency intervention by the Supreme Court, the case will soon move forward—and Mr Trump’s finances and potential conflicts of interest could be thrust into the public spotlight.

Standing is a curious bit of legal doctrine. The requirement is absolute—no litigant can bring a case without showing he has suffered harm, as per Article III of the constitution—but it is notoriously indeterminate. The Supreme Court’s three-part test from a 1992 case says a plaintiff must have sustained an “injury in fact” that is “concrete” and “particularised” and must be “actual” rather than hypothetical; that the defendant must have plausibly contributed to the alleged harm; and that the court is in a position to “redress the injury”. These requirements are easily listed; they are less straightforward to apply.

Judge Daniels found last year that Citizens for Responsibility and Ethics in Washington (CREW) and its co-plaintiffs, who argued that Mr Trump's “vast, complicated and secret” business interests create “countless conflicts of interest” in violation of the constitution, failed to satisfy the second and third requirements for standing. Hoteliers and restaurateurs in New York City who compete with Mr Trump’s businesses could not show that his establishments put them at a competitive disadvantage or that a court had the power to correct the imbalance. Judge Daniels also ruled that the litigants’ complaints did not come within a court's jurisdiction under the domestic and foreign emoluments clauses and involved political, not legal, questions. For all these reasons, Judge Daniels put a stop to the lawsuit against Mr Trump. It has been in limbo for nine months.

But on appeal, Judges Pierre Leval and Christopher Droney saw matters quite differently. In their decision at the Second Circuit the judges reignited the complaint, finding that the plaintiffs have a plausible argument for standing, after all. Even small injuries satisfy the burden, Judge Leval wrote, and plenty of evidence suggests Mr Trump’s status as president has turned his businesses into more lucrative enterprises. The president’s “establishments offer government patrons something that plaintiffs cannot”, Judge Leval explained: “the opportunity, by enriching the president, to obtain favourable governmental treatment from the president and the executive branch”. The “unlawful market skew” of Mr Trump’s hotels and restaurants ”directly affects” his competitors’ “revenue and profits”. There is no question this qualifies as “injury in fact”: “Every dollar of government patronage drawn to Trump establishments by the hope of currying favour with the president is a lost dollar of revenue that might otherwise have gone to plaintiffs”.

While the tenor of the Second Circuit decision suggests that the two judges in the majority believe Mr Trump’s holdings may violate the emoluments clauses—and threshold procedural questions have now been answered in the plaintiffs’ favour—this appellate ruling is far from a final resolution of the case. Instead, the lawsuit now returns to Judge Daniels in the district court. Joshua Matz, one of the lawyers representing the plaintiffs, says “it’s hard to predict” how quickly the lawsuit could proceed from here. Much depends on Judge Daniels. He could ask for more briefings on whether the plaintiffs’ complaints are valid claims under the emoluments clauses before ordering discovery—the evidence-gathering stage of the trial.

Once fact-finding begins (if things go that far) the case would hold, Mr Matz reckons, “extraordinary value”. The lawsuit “has already helped to educate the American people about the nature and importance of President Trump’s corrupt, self-serving conduct”, Mr Matz says, from foreign dignitaries converging on the Trump International Hotel in Washington, DC to Vice-President Mike Pence’s questionable stay at Mr Trump’s resort in Ireland earlier this month. Deepak Gupta, another lawyer on the case, says in a full trial “the public would learn what payments Mr Trump is receiving through his businesses from governments” and may get to “see Trump's tax returns—information that has been available for every other modern president”.

But given the glacial speed at which litigation proceeds through the federal courts, Mr Trump may complete his first term before the constitution's emoluments rules catch up with him. And chances of a big win for the plaintiffs, after the appeals courts and the Supreme Court have had their say, seem slim. Even if Mr Trump loses one of the three pending emoluments battles, the remedy will not be revolutionary: he could be forced to divest from his businesses or to place them in what the plaintiffs call a “truly blind trust”, but the Trump name would not be excised from towers, golf clubs and resorts around the world and Mr Trump would stay put in the White House. The main value of the lawsuits seems to be in what they could reveal about the president’s books along the way.