James: If Romney narrowly loses tonight, there is certainly a
rationale for him to continue. But I think his path to the
nomination becomes a lot harder. He is beating McCain among
conservatives, but not by the same margin that McCain is winning
among moderates. After tonight, McCain is going to further
consolidate the moderates. It isn't clear that Romney will be able
to further consolidate the conservatives.
Also, consider the media boost McCain got from a fourth-place
showing in Iowa (albeit just shy of third place) and a little
better than three-point win in South Carolina. A win in Florida
sends him into Super Tuesday with free media and a probable
infusion of cash, eroding Romney's biggest advantages.
Phil: I agree that even a victorious Romney will have a tougher
slog than McCain. But McCain needs to wrap this thing up before he
goes broke. Romney is much better positioned to afford a slower war
of attrition. And if there is any thinning of the conservative
herd, though I don't think that's likely, Romney could benefit even
more than McCain would by consolidating the GOP's moderate
minority.