Barack Obama's MLK speech at Ebenezer Baptist Church is extremely good. It should remind Obama fans of what they like best about him. For campaign purposes, though, I think nobody's ever doubted that he's a great orator. The difficulty is that he hasn't established a policy argument on his behalf that people find compelling. With little differentiation between the candidates in terms of issues, things are breaking down on demographic lines and women outnumber men, old people outnumber young people, nonblacks outnumber blacks, and working-class people outnumber college graduates among the target audience on the primaries.