For the purpose of the Democratic nomination for president, Sen Barack Obama’s so-called "race" speech today absolutely assured him the nomination.
First, he can’t lose the delegate race, even if he loses Pennsylvania big.
Second, he so eloquently addressed the issue of his pastor’s comments without throwing his spiritual mentor under the bus, there’s no way the superdelegates take the nomination away from him after he finishes first in the earned delegate count, though I am sure Hillary will try.
The general election will be a tougher road. But in my mind, his "imperfect union" speech is enough to win the Democratic nomination.