The Trump administration is arguing that a judge’s order to halt construction of a $400 million ballroom creates a security risk for the president. It is asking a federal appeals court to pause the ruling. In an emergency motion filed Friday, National Park Service lawyers say that order to suspend construction of the new facility was “threatening grave national-security harms to the White House, the President and his family, and the President’s staff.” U.S. District Judge Richard Leon in Washington last week ordered that unless Congress approves the project, which has included demolishing the East Wing of the White House, it must be put on pause.