Shouldn't you have reservations about Mitt Romney's ability to go up against Obama's machine if he can barely beat Santorum's disorganized campaign?
It depends how much it is due to flawed salesmanship, and how much to having to deal with an intractable wing of the party, with views that in a General are at once poor public policy and electoral suicide. The more it is the latter, the more the answer, is no, I for one don't have much concern. Most of the Pub Mittens resisters will be voting for him in the Fall. But flawed salesmanship is a more generic handicap, which would of course carry over as a problem in the General.
Make sense?
