This right here:
... is just about the best political speech I've ever heard. Maybe MLK beat it, and maybe Kennedy, but aside from that? Nobody.
(Really. If you haven't watched it, and won't get fired for doing so, do it. Yes, YOU.)
I'm not sure if Obama's sewn up the nomination, but he's managed to adroitly turn the issue around and reminded people why everybody thought he was a lock a month ago.