A month ago Mitt Romney's campaign was flying on all cylinders and doing well. Currently they have hit a bump in the road. Does that mean he will lose the GOP nomination? Not necessarily. Look at what happened to John Kerry in '04, he was written off as dead until he won in Iowa (some called it an upset).
The GOP traditionally doesn't make changes swiftly in the Presidential race. It is vital that Romney stay in the top-tier of candidates. In my opinion, as long as Speaker Gingrich stays out of the race, it is a three-man fight (McCain and Rudy are the others).
If Newt gets in, then he and Romney will duke it out for the 3rd spot.
My opinion, the momentum has shifted to Rudy. His poll numbers keep climbing, and as more "moderate" states move up their primary, he gets stronger and stronger. The other interesting thing to note is that McCain has been attacking Bush really strongly and his numbers have dropped. Is there a parallel, perhaps, but perhaps not.
Buckle up folks! We are in for a wild ride, and I haven't touched the Clinton-Obama fued.