A lawsuit was filed in federal court Monday by a team of ethics experts and legal scholars alleging that President Donald Trump’s overseas businesses violate the Constitution’s emoluments clause, which prohibits presidents from taking money from foreign governments.NPR reports that the group says it’s asking the court “to stop Trump from violating the Constitution by illegally receiving payments from foreign governments” with ties to Trump interests.

“These violations of the Foreign Emoluments Clause pose a grave threat to the United States and its citizens. As the framers were aware, private financial interests can subtly sway even the most virtuous leaders, and entanglements between American officials and foreign powers could pose a creeping, insidious threat to the republic,” the lawsuit states.

There are numerous examples of how Trump stands to make money by doing business with companies and other entities linked to foreign governments cited in the lawsuit, including the Industrial and Commercial Bank of China, which is owned by the Chinese government and is a tenant of Trump Tower in New York City. Its lease is expiring soon, meaning that the Chinese government will be in negotiations with the Trump Organization to renew the lease.

The Abu Dhabi Tourism & Culture Authority, which is owned by the government of the United Arab Emirates, is also a Trump Tower tenant.

According to the lawsuit, Trump collects royalties from his TV show The Apprentice and its spinoffs, and those shows air on broadcast networks owned or controlled by foreign governments.

Additionally, Trump properties in Indonesia, Turkey, the Philippines, Saudi Arabia and Scotland are cited as examples of properties that require various government permits and exemptions.

According to Citizens for Responsibility and Ethics in Washington , which is part of the suit, “When Trump the president sits down to negotiate trade deals with these countries, the American people will have no way of knowing whether he will also be thinking about the profits of Trump the businessman.”

CREW says that as a government-ethics watchdog, it has been harmed by Trump’s conflicts of interests because it has been forced to put more time and resources into opposing and publicizing them.

According to NPR, the legal scholars and former White House ethics officials filing the lawsuit include Richard Painter, former ethics adviser to George W. Bush; Harvard Law School professor Laurence Tribe; University of California, Irvine law school dean Erwin Chemerinsky; and Supreme Court litigator Deepak Gupta.

Courts have never ruled on how the emoluments clause relates to the president, NPR reports.

Trump’s lawyers have already indicated that they will oppose the suit.

Trump lawyer Sheri Dillon told a news conference recently, “No one would have thought when the Constitution was written that paying your hotel bill was an emolument.”

According to NPR, Trump’s son Eric told the New York Times, “This is purely harassment for political gain, and, frankly, I find it very, very sad.”