Police stand guard outside the Trump International Hotel on Pennsylvania Avenue in Washington as security tightens ahead of Friday's presidential inauguration. (John Minchillo/AP)

As he held court Thursday afternoon inside the ivory-and-gold ballroom of the Trump International Hotel, President-elect Donald Trump could not resist plugging the luxurious locale playing host to his Cabinet appointees, top Republican congressional leaders and hundreds of the GOP’s wealthiest donors.

“This is a gorgeous room,” the soon-to-be president said of his new hotel’s presidential ballroom. “A total genius must have built this place.”

Out in the airy lobby, where 4,000 red, white and blue balloons were cosseted in nets far above the crystal chandeliers, Trump supporters snapped selfies with incoming White House aides Kellyanne Conway and Sean Spicer and other boldface surrogates who waltzed through the room. Major party fundraisers from Texas and New York huddled at the marble bar. Waiters rang bells before sabering the corks off champagne magnums.

The U.S. Capitol is the backdrop for the official swearing-in ceremony on Friday, but the hub of inaugural action is Trump’s hotel, the site of a slew of official events and some of the week’s most sought-after private gatherings.

The main draw: “Donald Trump owns it,” said Doug Deason, a Dallas investor. “So many of the parties will be here. It’s electric — nobody wants to go to bed.”

(The Washington Post)

Nevertheless, after they awake Friday, the hotel will become the site of the first clash between Trump’s business interests and his presidency.

At 12:01 p.m., when Trump becomes president, he may be in violation of his lease for the building, which is owned by the federal government. The agreement includes a clause barring any “elected official of the Government of the United States” from deriving “any benefit” from the agreement.

Ethics experts warn of other potential conflicts. For instance, if the hotel continues to rent ballroom and meeting space to foreign officials, it could run afoul of the Constitution’s emoluments clause, which bars the president from accepting benefits from foreign leaders.

For his part, Trump appears unconcerned about using his weighty platform to promote his business. On Wednesday night, with members of the news media in tow, he made an unscheduled stop at the hotel on Pennsylvania Avenue NW, drawing applause as he worked the lobby, greeting friends and supporters.

Spicer, Trump’s incoming press secretary, dismissed questions about whether it was appropriate for the incoming president to be putting a spotlight on his hotel — even offering an endorsement of the facility.

“He is going to his own hotel?” Spicer said. “I think that is pretty smart. I think the idea that he is going to his own hotel shouldn’t be a shocker. It’s a beautiful place. It is somewhere he is proud of and symbolic of the kind of government he is going to run, ahead of time and under budget.

“It’s an absolutely stunning hotel,” Spicer continued. “I encourage you to go there if you haven’t been by. ”

President-elect Donald Trump gestures toward his wife, Melania, during a luncheon Thursday at Trump International Hotel. (Mandel Ngan/AFP/Getty Images)

[The Constitution may have something to say about how Trump runs his D.C. hotel]

Trump’s election in November kicked off a surge of interest in the luxury property, located in the historic Old Post Office Pavilion, which opened its doors in the fall. Rates this week were five times higher than normal – meaning many of the rooms are running at least $2,000 a night — and required a five-night minimum beginning Tuesday.

“Business is fantastic,” said the hotel’s managing director, Mickael Damelincourt. “The bar is packed every night. There is such a good energy to the place. I think it is really becoming a gathering place for Washington, D.C.”

On Thursday afternoon, well-heeled friends of the next president were ushered into a private room off the lobby marked “Trump Townhouse,” emerging with stuffed gift bags. An Ecuadoran official in town for the inauguration dined on tuna tartare at the bar. Longtime Trump adviser Roger Stone made a cameo in the lobby.

For Trump fans such as Vaughn Lower, who came from San Diego for the inauguration, it was the perfect place to be.

“I mean, where else would you want to be if you’re a Trump supporter?” said Lower, 28, his red “Make America Great Again” hat firmly in place as he worked the room, gathering signatures and snapping selfies.

Lower had scored autographs from Conway, Liberty University President Jerry Falwell Jr. and “Pawn Stars” star Rick Harrison in a black notebook he titled “The Inauguration Guest Book.”

Tara Memmen, 46, of Fairfax Station, Va., and Lisa McCollough, 46, of Coronado, Calif., arrived early with their families Thursday to have breakfast at the in-house restaurant, BLT Prime, then stayed for several hours to soak in the scene.

“It just feels like this is the very heartbeat of what Trump stands for, of what he has built from the ground up,” McCollough said. “Everyone wants to come and be part of it.”

Her 18-year-old son, Evan, excitedly rattled off everyone he had spotted: Spicer, Conway, Falwell Jr.

“I’m kind of star-struck, because I’ve been following the campaign for 18 months,” he said. Being in Trump’s hotel, he added, was “like the icing on the cake.”

Trump has turned over management of his business to his sons Donald Jr. and Eric, but he does not plan to sell his assets. He said this month that he would donate “profits” from foreign business clients to the U.S. Treasury. However, neither Trump nor representatives of the Trump Organization have provided details on how such payments would be tracked, collected and disbursed.

Given such issues, Rep. Elijah E. Cummings (Md.) and other congressional Democrats have pushed the General Services Administration to cancel the Old Post Office Pavilion lease.

GSA officials have said that no violations have yet occurred.

“No determination regarding the Old Post Office can be completed until the full circumstances surrounding the ­President-elect’s business arrangements have been finalized and he has assumed office,” the agency said in a statement.

[Update: Feds say it’s ‘premature’ to judge lease for Trump’s D.C. hotel]

By then, of course, GSA will be part of the new administration — raising the prospect of a Trump appointee renegotiating the lease with one of his sons.

Steven L. Schooner, a professor of government procurement law at George Washington University, said he feared that the GSA would “just bury its head in the sand and hope the storm blows over” even though “this problem isn’t going to get better with time.”

“Anything they do will be heavily scrutinized and, as we’ve seen, the Trump Organization pulls no punches in attacking its enemies, all too often without regard for objectivity, facts, or principles,” he said. “Just think about it: Who wants to go to war with the president, who selects your bosses and replaces them at will?”

Rosalind S. Helderman contributed to this report.