The only way to answer the question in the title of this post is to ask a second question: “Compared to what?” I see a lot of people piling on Romney, but fewer people thinking this through.
First, you can ask about Romney compared to some other specific Republican. If that’s the question, it’s hard to say that Romney is definitively worse. Than the other candidates who ran in the primary? Gingrich, Santorum, etc.? Than candidates who didn’t run, like Christie or Daniels or Thune or whoever? I caution against assuming that there was some savior waiting in the wings. Remember when that savior was going to be Rick Perry or, back in 2008, Fred Thompson? The fact is, once any candidate gets in the race, the bloom comes off the rose and we quickly discover their shortcomings as well. Maybe one of these candidates would have been slightly “better” than Romney as of September 2012, but that’s not a slam-dunk case.
Another way to answer “compared to what?” is to compare where the race stands now to what the fundamentals would predict. Let’s say Obama will beat Romney by something like half a point (in the two-party vote). That is based on a statistical averaging of the various forecasting models by Jacob Montgomery et al., which pegs Obama’s share of the two-party vote at 50.3% (see here). At this point, with Obama’s convention bump perhaps dissipating somewhat (or perhaps not?), Romney trails Obama by 3 points, according to Pollster. So, by this reckoning, Romney’s running about 2.5 points behind where he “should” be—although there is reason to suspect that this gap will close.
But if you don’t take the Montgomery et al. averaging of the models as the definitive take on the fundamentals, and you believe the forecasts that are more optimistic for Obama (like the one Lynn and I present in The Gamble, or the Erikson and Wlezien model here), then in fact Romney is not under-performing right now. In fact, maybe Obama is (slightly).
I’m not suggesting that we can definitively settle this now. But I don’t think we can say with confidence that Romney is significantly worse than a generic GOP candidate. We’ll have a better sense in November, obviously.