Joe Biden vowed to unite an America torn by crisis and contempt Thursday night, accepting the Democratic presidential nomination and achieving a pinnacle in an unfinished quest that has spanned three decades and been marred by personal tragedy, political stumbles and more dynamic rivals.The past hurdles fell away as Biden addressed his fellow Democrats and millions of Americans at home who he hopes will send him to the White House to replace Donald Trump – though his triumphant moment was drained of immediate drama by the coronavirus pandemic, which left him speaking to a nearly empty arena rather than a to a joyously cheering crowd. ‘Come together’: Biden kicks off battle with Trump for U.S.