So what does the "race speech" tell us about how Obama thinks? How does it fit in with the unity-mongering and meeting-with-foreign-dictators stuff?
At bottom, I think Obama's basic theoretical framework is in dispute resolution. The worldview is sometimes attributed to his experience as an organizer, but it could also be that of a corporate litigator. He thinks of the world as filled with non-zero-sum games, in which the win-win alternative of making a deal and dividing the surplus isn't taken because each side is gripped with a narrative that makes rationally self-interested compromise difficult or impossible. The intellectual problem is to look at the interests coolly and dispassionately and see where the surplus-maximizing position lies. But the harder problem is to be sensitive enough to how the identity-constituting stories keep both sides from doing that. It's Harvard Negotiation project stuff, but it also works with who he thinks he is.
Obama doesn't particularly claim to come from nowhere or have no loyalties. He is instinctively cosmopolitan, on-the-left and tied to his adopted black American Protestant identity. But I think he recognizes that to advance the interests he is loyal to requires figuring out what other people's loyalties are, "recognize" them and then figure out how to get to the best possible resolution of the bargaining problem they represent.
Obama loves to put things dialectically. In this, the successful politician he most resembles is Tony Blair. His central rhetorical trick is restating positions he is arguing attractively and strongly, but in such a way that they obviously have limitations he hints at transcending. Dreams From My Father is hardly a black nationalist book -- but it engages very sympathetically with black nationalism, not unlike the way in which Audacity of Hope engages sympathetically but critically with fusionist conservatism. In Dreams, black nationalism is twinned not with white racism, but with the white romantic liberalism of the family he grew up with. The good thing about that liberalism is that it tries to transcend tribalism -- the bad part is that tribalism is too central to the human condition to be transcended. In fact, much of what is most admirable about liberalism comes from the folkways of Northern European Protestants -- not that there's anything wrong with that.
Obama thinks he solves the dilemma by making the same move Rawls made in Political Liberalism towards incompletely theorized common ground across more comprehensive narratives. The master discourse though is narrative negotiation, not procedural justice.
Interestingly, I think McCain also represents a reaction to the dilemma of a universalist liberalism rooted in particularist traditions it is unable to defend. But he responds differently.
Pithier Version for Canadians: Obama isn't Trudeau. He's Mulroney.