The organisation argues that the project is moving forward unlawfully and without the federal reviews required to protect one of the nation’s most significant historic sites.

Chartered by Congress in 1949 to safeguard places of national importance, the National Trust contends that the Administration began construction without submitting plans to the National Capital Planning Commission, as mandated by the National Capital Planning Act.

The suit also asserts that no environmental assessment or Environmental Impact Statement has been completed under the National Environmental Policy Act (NEPA), and that Congress has not authorised the project—an essential step for any new construction within federal parkland, including the White House and President’s Park.

“The White House is one of the most powerful symbols of American democracy,” said Carol Quillen, president and CEO of the National Trust for Historic Preservation. “Review by the National Capital Planning Commission helps ensure that any changes respect the site’s historic character. Public comment is equally vital - it reflects the values of a government of the people, by the people, for the people.”

The suit further argues that by bypassing these legal requirements, the President is violating the Constitution’s Property Clause, which grants Congress authority over federal property.

In October, the National Trust urged the National Capital Planning Commission, the National Park Service, and the Commission of Fine Arts to pause construction until the required reviews were completed. While acknowledging the need for expanded meeting space, the organisation warned that the proposed ballroom’s scale and height would overshadow the White House and permanently disrupt its classical architectural balance, citing the Secretary of the Interior’s Standards for Rehabilitation.

Those concerns, the Trust notes, went unanswered.

The National Trust is the sole plaintiff in the case and is represented by Foley Hoag LLP. The organisation says it remains ready to work with federal agencies to explore alternative designs that meet the Administration’s functional needs while preserving the historic integrity and symbolism of the People’s House.

Since the legal challenge was lodged, President Trump has sought to push the project through the federal government’s review process at a rapid pace, potentially clearing the way for construction to start in April.