WASHINGTON — The Trump International Hotel, five blocks from the White House, is a welcoming place for Trump administration officials and their supporters — and an ongoing legal headache for the president.

The Trump Organization spent $200 million transforming the Old Post Office into a five-star hotel that harkens back to the Gilded Age. It opened right before President Donald Trump's upset victory in the 2016 election, and soon became a magnet for Trump backers, and for other customers whose patronage was more problematic.

Eighteen months into the Trump presidency, an NBC News analysis of public filings and social media indicates substantial spending at the hotel by federal agencies, Trump's political allies and foreign governments.

Trump supporters enjoy coming to the bar and cavernous lobby to see and be seen, and for them it's not a bad thing if a member of the administration or the Trump family happens to be there to notice they are patronizing the hotel.

"Who doesn't want to come and have a chance to see the vice president, the secretary of the treasury, Kellyanne Conway or even the president himself?" asked Nicole DiCocco, a Trump loyalist and a member of a Palm Beach-based group that calls itself the Trumpettes.

DiCocco has photographs of herself at the hotel with Vice President Mike Pence, Rudolph Giuliani, Sarah Palin, Larry Kudlow and such Trumpworld stars as Diamond and Silk, Eric Bolling and ex-aide Corey Lewandowski, among others.

It's another group of people who may want to be noticed by Team Trump, however, who are at the heart of the hotel's current legal worries.

Soon after Trump took office, the governments of Azerbaijan, Bahrain and Kuwait held official events at the hotel. And three days after his inauguration, the president was hit with his first lawsuit over that kind of lucrative booking.

Nicole DiCocco poses in the lobby of Trump International Hotel with Rudolph Giuliani, left, and Rep. Peter King, R-N.Y. Courtesy Nicole DiCocco

The plaintiffs say the hotel is not just a conflict of interest, but a violation of the Constitution, which includes emoluments clauses designed to keep officials from profiting from their positions or being influenced by gifts or benefits from foreign powers.

According to Trump's financial disclosure forms, he took in more than $40 million in revenues from the hotel in 2017. Ivanka Trump's financial disclosure forms show she took in $3.9 million in revenues from the hotel. The Trump Organization is a private company so the hotel's vacancy rates and details on who spent what there are not available.

An NBC News analysis of everything from Federal Election Commission filings to Twitter, however, indicates that foreign governments, Republican Party organizations and federal government agencies have all spent significant sums at the hotel since the president took office.