K, just did. Even in quotes, it's pretty slim pickings. (That is, there are a few hits, but it's not exactly a common slur).

I'm just saying, look, there is a lexicon of coded racist language in American political discourse that is very widely accepted and espoused by mainstream Republicans all the time. Newt Gingrich and his remarks about the NAACP needing to get away from foodstamps, e.g., or "welfare queens" and what have you. The idea that Santorum, in a speech he has probably delivered dozens of times, would almost drop the n-bomb, seems unlikely.

Plenty of words start with a "nig/neg" sound in spoken American English. Negotiation, negative, negligence, or any of their variants, seem much more likely candidates for the flub. Again, I'm really not trying to excuse Santorum for anything. I just don't see how this is a smoking gun. It's a stretch, at best, and at worst, our acting like it's definitive proof of Santorum's racism takes away from some of the more really reprehensible shit he's said.