FILE - In this Aug. 28, 1963, file photo Dr. Martin Luther King Jr., center left with arms raised, marches along Constitution Avenue with other civil rights protestors carrying placards, from the Washington Monument to the Lincoln Memorial during the March on Washington. Next Wednesday, the nation's first black president, Barack Obama, will stand near the spot where Martin Luther King Jr. stood 50 years ago, a living symbol of the racial progress King dreamed about, and enunciate where he believes this nation should be headed. (AP Photo, File)