Whoever wins in Iowa tonight, it won't be Gingrich. And he's hopping mad. The negative adds by pro-Romney PACs have had their effect--not that they shouldn't have as Gingrich is a very bad dude and if the only two politicians left in the world were Romney and Gingrich, I would certainly have to go with Romney.
Watching Chris Matthews on MSNBC Hardball last night, the contrast between the good-looking, family-man Romney and the ugly attacks on Gingrich by Romney surrogates led even Chris to feel a little sorry for Gingrich. Gingrich is certainly feeling sorry for himself comparing himself to John Kerry, of all people, being "swift-boated" ["Romney-boated."]
Romney and his friendly PACs probably did what they had to do perceiving Gingrich as their biggest threat overall. Now Gingrich's bubble has burst but he's going on, probably only about as far as South Carolina, but by way of New Hampshire and all his political and personal arsenal is targeted on Romney. Gingrich has sworn off his original strategy of running only a "positive" campaign. It's now a grudge match.
If Gingrich has any political talent at all it is in organizing political opposition movements. Romney is still the likely winner in New Hampshire and the inevitable winner of the Republican nomination. But it's going to get pretty ugly.
Oh, and newts really do have teeth. I looked in up on Wikipedia.
Addendum, slightly later:
I just realized why Romney has been getting a pass on negative campaigning against him. All the other candidates, even as they surge and bust as the anti-Romney, are still hoping to be his VP choice. Gingrich would never want that so he is free now to go on the attack, his cheap "no-negative-campaining" strategy now having failed.
Romney, being a little thin-skinned himself, isn't likely to choose one of his competitors. He's going for a Chris Christie or Marco Rubio for his VP.