A political activist and a Vietnam veteran represented by an anti-corruption organization filed a lawsuit on Saturday challenging what it called the “night of cage fights” that President Trump planned to hold at the White House as part of the celebration of the country’s 250th anniversary.
The case was filed just over a week before the event, which is scheduled for June 14 and is being organized by the mixed-martial arts promotion Ultimate Fighting Championship. The White House has been overshadowed in recent weeks by the construction of the venue for the fights, which includes a 600-ton steel arch on the South Lawn.
The lawsuit argues that the transformation of the grounds was never authorized by Congress, and that the event will serve as an extraordinary use of government space to benefit both the chief executive of U.F.C., Dana White, and Mr. Trump, who is an investor in U.F.C.’s parent company.
“The president is giving White and his company what none have enjoyed before: unfettered access to the White House and Lincoln Memorial to stage a private, for-profit sports event, with all the promotional and branding opportunities that accompany such access,” the lawsuit says. The Lincoln Memorial is scheduled to host ceremonial weigh-ins for fighters before the event.
The White House and U.F.C. did not immediately return messages seeking comment on Sunday.
Beyond the procedural claims that the lawsuit skipped an environmental review and took over federal spaces for an event without the approval of Congress, the case focuses heavily on questions of improper financial gains.
It cites reporting that U.F.C. was selling premium tickets to the event for more than $1 million, and the fees that Paramount Skydance, the media company owned by two other executives with ties to the president, Larry and David Ellison, will collect for streaming the event. The suit also notes that Mr. Trump purchased between $15,000 and $50,000 worth of stock in TKO Holding Group, the parent company of U.F.C., in March — while he was in the process of promoting the event.
Though Mr. White and U.F.C. have billed the event as part of the 250th anniversary celebrations, the fight is being held almost three weeks before Independence Day, on Mr. Trump’s 80th birthday.
“The event is neither ‘for the celebration of the 250th anniversary of American independence’ nor, crucially, being ‘planned, organized and executed’ by the federal government,” according to the suit.
As in other cases challenging abrupt changes Mr. Trump has made to Washington, such as his plans to build a 250-foot triumphal arch near Arlington National Cemetery, the suit says the event will cause an “aesthetic injury.” Beyond the South Lawn and the Lincoln Memorial, the fighters in the event are also expected to “make prefight walkouts” from the Oval Office, according to the lawsuit.
The plaintiffs in the case are Susan Douglas, a retiree and political organizer, and Paul Romano, a Vietnam War veteran. They each argue in the lawsuit that they frequent the area and were offended by the spectacle being held outside national monuments. The Public Integrity Project, a nonprofit group focused on good governance and public corruption, is representing them.
The case was assigned on Sunday to Judge Amit P. Mehta, an Obama appointee in Federal District Court in Washington who will face the early question of whether the plaintiffs face direct harms because of the event in such a way that they can sue.
The U.F.C. event was scheduled to take place a year after Mr. Trump staged a military parade in Washington to mark the 250th anniversary of the Army, which also coincided with his birthday.
