The difference between Blowfly and Barack Obama is like the difference between Public Enemy & Eminem: Back when Flavor Flav couldn't give a fuck about the Grammys, it was because he couldn't have imagined winning one. When Eminem recycled the reference, a decade down the line, he'd already scored two of them.The second half is about the Leiber and Stoller song "Only in America", which is a footnote in the endless history of black/Jewish relations in America.
So one thing that'll happen if Obama goes the distance is, a long tradition of African-American songs - rooted in the notion that no black man will ever occupy the office - will grind to a halt. (An old joke, along the same lines: "I firmly believe that, one day, a man in a kippa and prayer shawl will sit in the Oval Office.... Unless, of course, he's Jewish.")
By complete coincidence, Diddy Wah has a post about the other great black president, Fela Kuti.