Washington DC - President Donald Trump's administration asked the Supreme Court on Friday to allow it to complete construction of a large ballroom at the White House.
Solicitor General John Sauer made the request in an emergency appeal to the conservative-dominated top court, which includes three justices nominated by the president.
Trump ordered the demolition of the historic East Wing of the White House last year to make way for a massive ballroom, but the project has been tied up in the lower courts.
An appeals court last week upheld a district court order halting work on the ballroom but put its ruling on hold to allow for the administration to appeal to the Supreme Court.
The US Court of Appeals for the DC Circuit agreed with the lower court that such a sweeping White House overhaul required the explicit consent of Congress.
Trump lashed out after the 2-1 ruling, calling it "horrendous, politically motivated, and unlawful," and said he would appeal to the Supreme Court.
The president initially touted the construction of the ballroom as being necessary to host galas and state dinners, but has since repeatedly pointed to the addition of an underground military bunker and other security features.
The solicitor general, in the appeal to the Supreme Court, also emphasized the security aspects of the project.
Trump insists ballroom is "vitally" important for national security
"This case involves an extraordinary and unlawful injunction that will halt the ongoing construction of the integrated military complex, including a totally secure ballroom space, at the East Wing of the White House, which is vitally required by national security," Sauer said.
"The President of the United States of America is not a tenant, but rather the sole, elected head of the Executive Branch, and Congress has authorized him to renovate, secure, and protect the White House and its grounds, as other Presidents have been allowed to do, without exception," he added.
Work on the project began last year with the sudden demolition of the East Wing, which used to house the offices of the First Lady.
Trump has insisted that the ballroom will be privately financed, but media reports in June showed that significant taxpayer funds were going to the project, which could cost as much as $600 million.
The ballroom is just one of Trump's pet projects to leave his mark on Washington by the time his second term ends in January 2029, along with a renovation of the Lincoln Memorial Reflecting Pool and other parks, and the construction of a gigantic arch.
Several of the projects have similarly faced legal challenges, but the ballroom project is the first to reach the Supreme Court.