A federal judge set new limits on President Donald Trump’s planned White House ballroom, saying construction could proceed only on an underground portion of the project deemed necessary by the military, and not on the 90,000-square-foot aboveground addition that Trump has eyed to entertain VIP guests.

“National security is not a blank check to proceed with otherwise unlawful activity,” U.S. District Judge Richard Leon wrote Thursday. He said the Trump administration could also take steps to secure the construction site to make it safe for people on the White House grounds.

Leon, an appointee of President George W. Bush, last month ordered a halt to Trump’s planned $400 million project, ruling that it could not continue until the president obtains approval from Congress. But Leon permitted further construction to ensure “the safety and security of the White House” after Trump officials said work on an underground emergency bunker was necessary to protect the president, his family and his staff......

“No matter how much the Defendants insist otherwise, the lack of a massive ballroom on the White House grounds is not a national-security emergency,” lawyers for the National Trust wrote in a filing Tuesday. They noted that Trump continues to live at the White House and entertain foreign dignitaries, despite the administration’s claim that the current situation poses a security risk.

The National Trust’s lawyers also called attention to the Justice Department’s shifting arguments over the project’s scope. The Trump administration initially maintained that the underground work was separate from the aboveground ballroom, an argument that Leon considered when he declined to pause the project last year and allowed the underground work to continue.