The case being heard Wednesday was filed days after Mr. Trump took office by Citizens for Responsibility and Ethics in Washington, or CREW, a bipartisan watchdog group. CREW’s complaint highlights the conflicts between Mr. Trump’s duties as president and his “vast, complicated and secret” web of business interests. These include Trump Tower in New York, where foreign-government-held entities like the Industrial and Commercial Bank of China hold leases that will come up for renewal during Mr. Trump’s term, and the Trump International Hotel in Washington, where foreign diplomats pay top dollar to sleep, eat and do business with the United States. (Elected federal officials, including the president, are prohibited from holding the lease to the hotel, but that’s another story.)

Since the emoluments suit was filed, plaintiffs who complained of unfair competition in the hospitality industry have joined in. Meanwhile, two separate federal suits have also charged Mr. Trump with violating the emoluments clauses — one by nearly 200 Democratic members of Congress and the other by the attorneys general of Maryland and the District of Columbia.

A central question for the courts is the meaning of “emoluments.” Does the term cover only those benefits given in exchange for an official’s “personal services,” as the White House contends? Or does it apply to “anything of value” an official receives, as the plaintiffs argue? At Wednesday’s hearing, Judge George Daniels of Federal District Court appeared sympathetic to a broader reading, but was skeptical that the plaintiffs have standing to bring the lawsuit, because they had not shown concrete ways that Mr. Trump’s actions had directly harmed them.

Even if the case is thrown out on those grounds, Mr. Trump is still a walking emoluments-clause violation. And he still refuses to release his tax returns and other financial records, preventing the public from seeing the full extent of his business entanglements, debts and interests.

In this light it’s hard to see how the American people can ever be confident that Mr. Trump, who has spent a lifetime as a money-obsessed deal maker, is acting in the nation’s best interest, and not his own.