President Donald Trump's "emoluments clause" problem is compounding.

The attorneys general of Maryland and the District of Columbia (both, for what's it's worth, Democrats) announced that they had filed a federal lawsuit on Monday accusing Trump of violating the increasingly well-known clause of the Constitution by accepting payments from foreign states through his sprawling business empire.

"When the president is subject to foreign influence, we have to be concerned about whether the actions he's taking – both at home and abroad – are the result of payments that he is receiving at the Trump Hotel, payments that he is receiving at Mar-a-Lago, payments that he is receiving at Trump Tower, payments that he is receiving in all of his other far-flung enterprises, and he brags about it," Maryland Attorney General Brian Frosh told the Associated Press. This follows on a suit brought earlier in the year by Citizens for Responsibility and Ethics in Washington on the same topic; and Democratic members of Congress are reportedly preparing a suit of their own along the same lines.

If you're among the diminishing number of people who are unfamiliar with the clause at question, Article I, Section 9 of the Constitution prohibits anyone holding U.S. office from accepting "any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince, or foreign State" without the Congress' consent. An emolument, per "Webster's New World Dictionary," is a "payment received for work, salary, wages, fees, etc."

Basically, the Founders didn't want foreign governments to be able to funnel, say, money to our officials in an effort to influence them. The ethics group and now the attorneys general argue that Trump receiving money from foreign governments through the businesses bearing his name, which he still owns, violates this clause.

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For its part, the Trump administration dismisses the concerns, arguing that Founding Fathers like George Washington sold grain to foreign governments so it must be OK for the current president to keep raking in bucks from other states as well.

For the record, per Politico Magazine's Joshua Zeitz, there's no record that Washington did business with foreign governments; and, he argued in a piece Saturday, the Justice Department's case is more broadly "historically illiterate":

The Emoluments Clause was meant to prevent exactly the situation that many of Trump's critics and skeptics now fear: the elevation to high office of men and women who are deeply indebted to, and economically dependent on, outside actors – worse, still, foreign actors who knowingly use patronage and pressure to make slaves of free men. Substitute Vladimir Putin for King George, and you can effectively resurface the same battle-worn tracts from the 1770s and 1780s.

Trump is, Zeitz argues persuasively, "the eventuality [the founders] feared above all."

But take a step back from the legal and historical arguments and consider: The Department of Justice is defending Trump's right to keep his numerous and broad pockets open for foreign governments to pour largely undisclosed sums of money into.

Which foreign governments are lining those pockets and with how much money? We don't know because Trump's business dealings remain almost impenetrably opaque and because his business is making only a de minimus effort to follow the flimsy promises he made in January about separating his financial interests from the presidency, including donating profits from foreign governments.

So we get occasional, tantalizing glimpses into the intersection of Trump's businesses and foreign governments. Take the Trump International Hotel in Washington, D.C., for example, which lost more than $1.1 million last September and October, its first two months in operation, but has turned into a networking and social hub with its owner occupying the White House.

"Foreign governments seem particularly keen to patronize Trump's property," Time magazine reported recently, detailing how countries like Saudi Arabia (whose lobbyists have spent more than $270,000 there), Bahrain, Kuwait and Azerbaijan have made sure to patronize the property. "Why wouldn't I stay at his hotel blocks from the White House, so I can tell the new president, 'I love your new hotel!' Isn't it rude to come to his city and say, 'I am staying at your competitor?" an Asian envoy told The Washington Post after the election last November.

Maybe it's purely coincidental that Trump made his first foreign trip as president to Saudi Arabia and then sided with that country in a regional dispute against Qatar, which The New York Time described as "America's most important military outpost in the region." (A fact of which Trump, ahem, may not have been aware.)

Who else has had events or found other ways to pour money into the hotel? We don't know – the business has a policy of not revealing such information.

And while Trump's hotels and who stays or otherwise spends money there are perhaps the highest profile venue through which foreign agents can augment the president's coffers, they're not even the yugest. As I wrote last month:

"The big money is not the hotel rooms," says Painter. "The big money is going to be the financing … of all these companies he has an interest in." To whom is the Trump Organization – and by extension Trump himself – indebted? We still don't know, and Trump refuses to disclose his tax returns which would help get at some of that information. "What they need is for every one of those corporations that he has a controlling interest in, we need to find out who's providing the other equity capital and who is providing major loans, that capital to these corporations," says Painter, who is on the team of lawyers which has sued Trump over emoluments.

A lengthy new article on the emoluments clause in New York magazine by my friend Andrew Rice illustrates some of the dangers here. It relays the case of Mukemmel Sarimsakci, a Turkish immigrant and Dallas-based real estate developer whose firm has what The New York Times called "vast foreign ties to Russia, Kazakhstan and at least two dozen other countries." Shortly after Trump's inauguration, Sarimsakci revealed an agreement to build one of a new line of Trump hotels in Dallas; he planned to finance the project with money from private investors from Turkey, Kazakhstan and Qatar.

There's no indication that any of this money would have come directly from foreign governments but that's really beside the point: Thanks to Trump and his minions' opacity – including his ludicrous refusal to follow the standard procedure of releasing his tax returns for public consumption – there's no way for the public to know with whom exactly he is in business. The Sarimsakci deal ultimately fell through in part, at least, because he had gone public with it.

Can we rely on the good sense and/or rigorous ethical standards of Team Trump to ensure that foreign governments aren't using business deals to boost the U.S. president's bottom line? It seems unlikely. As I said, the company itself is already undercutting his promises to avoid foreign profits on the grounds that both it's just too darn hard and that it would "diminish the guest experience of our brand."

And Trump himself has been laughably cavalier about the matter of presidential ethics: "The law's totally on my side, meaning, the president can't have a conflict of interest," he told The New York Times last November. Actually, he's got that backward: Congress has exempted the president and vice president from conflict-of-interest laws, meaning in effect that the occupant of the Oval Office can in fact have conflicts of interest. Undergirding that system is the presumption of a president who won't abuse that privilege. But Trump seems to confuse that exception with a license to profit from the presidency.