No way. A win for any frontrunner is good for them. They score points and eat up some of the clock.
I don’t see a win for Romney in IA or NH doing anything but helping him tread water unless he gets 50% or more of the vote. We are talking momentum here. When everybody expects you to win, it doesn’t give you much of a bump because they’ve already discounted it and moved to the next race. If he wins decisively in a early southern or western state like SC, then we know he’s for real.