Lawyers representing the federal government argue that a court cannot stop construction of a White House ballroom because it was already underway and because of the sensitive security concerns they say the structure is meant to address.

President Trump's White House ballroom plans are in the hands of three appellate judges who will hear arguments over whether construction should be allowed to continue.

Preservationists sue over ballroom construction without authorisationAppeals court allows construction to continue during legal battle, no ruling on merits yetAdministration…