WASHINGTON, June 12 : A federal judge declined on Friday to block President Donald Trump from hosting a special Ultimate Fighting Championship mixed martial arts event on the White House grounds, letting the fights set to be held on Sunday inside a towering new structure proceed. U.S. District Judge Amit Mehta ruled against two Washington-area residents who argued in a lawsuit that Trump's administration exceeded its authority for the event, dubbed "UFC Freedom 250," by among other things failing to obtain congressional authorization. The plaintiffs had sought a judicial order to block the event.The UFC event is scheduled to take place on Trump's 80th birthday as part of the Republican president's plans to celebrate the 250th anniversary of the founding of the United States. The event feat