1) They want change!they feel that all those presidents we have had who are white Christians that are conservatives or moderates have been leading us in the wrong direction, it is time to try a Black liberal who will think up some new ideas.2) They are Blacks or Muslims who want a president who is like they are. Or they are cynical republicans who believe that white folks won't vote for a Black man in the real election, so they are making 0bama the democrats nominee (on the theory that any idiot their party runs will win, if he is white)