If Bush gets 15% of the black vote in 2004 he is guaranteed reelection.
True enough, because other demographic groups would likely break the same way. 15% of the black vote probably means Bush would get a majority of the Hispanic vote, white vote, etc.
That said, I'll eat my cyberhat if Bush receives 15% of the black vote in 2004. The Democrat has received at least 83% of the black vote in each of the last 10 elections.