The action is being cooperatively filed with District of Columbia AG Karl Racine.
They contend in a federal lawsuit filed on Monday that he's corruptible to foreign governments. In the Los Angeles Times, a May 14 op-ed claimed "the Constitution's emoluments clause" is based on "a dread of corruption" from "officeholders" tainted by "the scrum of the marketplace", and that Trump's continuing business holdings are "violating it". "If that's not a harm to every American citizen and every resident in the District of Columbia and Maryland, I don't know what is". Trump warpath, part one: The president has. The lawsuit accuses President Trump of violating both. Since then, a restaurant group and two individuals in the hotel industry have joined as plaintiffs.
During Monday's White House Press Briefing, spokesman Sean Spicer said the suit was brought by two Democratic Attorneys General and an "advocacy group with partisan ties".
"It actually started with a press conference as opposed to filing it, which is interesting", Spicer said.
"It's not hard to conclude that partisan politics may be more the motivations behind the scenes", he added.
The D.C. Attorney General's office told CNBC via email that more details would be provided at a press conference at noon Eastern time on Monday.
The Justice Department had no immediate response. The president called an earlier, similar lawsuit about the so-called emoluments clause of the Constitution an issue "without merit, totally without merit".
The attorneys general didn't have to do much investigation to make their own case. Frosh said the president has discussed some of his business dealings on the campaign trail, noting Trump's mention that a state-owned Chinese bank has office space in Trump Tower in NY. "I don't think he's giving it to them for free, and there are many sources that have given us information about the payments that he has received".
The attorneys general cite the emoluments clause of the Constitution which has never before been heard by the Supreme Court or federal courts. Some congressional Democrats are expected to file a third lawsuit arguing the president's behavior is also unconstitutional as early as this week.
After the President handed day-to-day operations of Trump Organization to his sons, the company claimed it would identify foreign revenues and donate them to the US Treasury in order to avoid implicating the emoluments clause.
If a federal judge allows the case to proceed, Racine and Frosh say they will demand copies of Trump's personal tax returns in court to gauge the extent of his foreign business dealings.
"It is unprecedented that the American people must question day after day whether decisions are made and actions are taken to benefit the United States or to benefit Donald Trump", he said. The shaping need not entail a specific quid pro quo with a foreign state; general affinities or preferences, or a natural inclination to favor those who have bestowed favors-or profitable business-in the other direction may be sufficient to shape policy in ways detrimental to USA interests.