A federal appeals court has halted construction on President Donald Trump’s proposed $400 million White House ballroom, ruling that the administration must obtain congressional approval before moving forward with the project.

In a 2–1 decision, a panel of the U.S. Court of Appeals for the District of Columbia Circuit upheld a preliminary injunction requested by the National Trust for Historic Preservation. The organization sued to stop construction after the administration demolished the White House’s East Wing to construct the 90,000-square-foot ballroom without authorization from Congress.

Writing for the majority, the judges emphasized that the President lacks the constitutional authority to unilaterally demolish and rebuild portions of the White House complex. The court noted that its decision does not weigh in on the merits or desirability of the ballroom itself, but rather enforces the legal requirement for legislative authorization.

The appeals court placed a 14-day stay on its order, giving the Justice Department time to appeal the ruling to the full D.C. Circuit or petition the U.S. Supreme Court.