A divided Supreme Court on Monday allowed construction to continue on President Trump’s luxury White House ballroom, which has been steadily rising to replace the East Wing the president tore down last fall.

In a 5-to-4 vote, the court said the preservationists who challenged the construction of the planned 90,000-square-foot ballroom did not have legal grounds known as standing to bring their lawsuit because they were not directly harmed by the project, estimated to cost $400 million.

The majority emphasized that its order was not addressing the legality of the project and instead the question of who could sue to try to block it. But in practical terms, the order was a significant setback to the most serious legal challenge to the project, meaning the president seems likely to be able to complete construction. Halting the project now would probably require a fresh lawsuit from an individual or group with standing, such as Congress, which would be a nonstarter while Republicans control the House and Senate.

In an unusual lineup, Chief Justice John G. Roberts Jr. and the court’s three liberal justices dissented, saying the construction was “likely unlawful.”

The White House is “an iconic American building whose symbolism and history are wrapped up in its architecture,” the chief justice wrote in a lengthy dissent that quoted from Winston Churchill and Theodore Roosevelt. “All the more reason to ensure that those responsible follow the rules in deciding what to tear down and what to build up at the People’s House.”

Monday’s order reversed lower-court rulings that would have halted aboveground construction because the judges found that the administration had exceeded its authority by moving ahead with major changes to the White House campus without congressional approval.