Donald Trump Jr. said recently that the suggestion his father donated millions of dollars to run for president against a deep Republican field and Hillary Clinton in order to make money was without any merit. "That doesn't make any sense whatsoever," he said.

Gross and Pitts seek no damages, but rather an order barring Trump's Washington hotel business from operating while President Trump owns it. Attorneys are representing the couple on a pro bono basis and include Alan Morrison, dean of public interest law at George Washington University and co-founder, with Ralph Nader, of the Public Citizen Litigation Group in 1972.

The complaint cites Trump's appearances at the hotel, its hosting of foreign embassies and White House Press Secretary Sean Spicer's comments saying, shortly before the inauguration: "It's an absolutely stunning hotel. I encourage you to go there if you haven't been by."

"This is a company town and the business is the government," Pitts said. "We have people, individuals, companies in the U.S. and around the world who do business with the government. And the business leader of the government is the president of the United States."

Cork's co-owners do not name any specific client they have lost to Trump, though they say business around the inauguration fell well short of what they experienced in 2009.