 CBS News special report. California Congressman Adam Schiff has added his name to the list of top Democrats backing Kamala Harris' new bid for the presidential nomination. So has Kentucky Governor Andy Beshear. And West Virginia's independent Senator Joe Manchin tells CBS News he will not mount a challenge to a Harris nomination. Still, he believes... Neither side can win without the sensible, moderate middle. They can't do it. CBS's John Dickerson.