Charles Franklin has a chart today that's getting a ton of play which shows Rick Perry's polling numbers dropping and attributes it to his awful debate performances. I think it's clear that Perry's position vs. Romney has deteriorated since he first announced that he was in and jumped out to a lead, and that Perry's debate performance has been awful. But is that what's driving things?
I have no idea, but I'm somewhat skeptical. Matt Yglesias explains why debate performances certainly can matter during nomination contests -- basically, there is little to differentiate the candidates and so campaign effects of all sorts are likely to be important -- but that doesn't mean that the debates are driving anything right now. After all, we've seen this before more than once this year: new candidate jumps in or gets a sudden burst of publicity, and spikes up in the polls...and then falls back. I think it's very, very, likely that Perry's August lead was at least in part a bounce that was likely to dissipate regardless of what happened in September. Of course, had he generated good news over the last month, he might have been able to deflate the bubble more slowly, so in that sense, I suppose I can't disagree with Franklin.
All that said, we can conclude two things. One is that if Perry did have a chance to put this thing away quickly, as in by Halloween, that's gone now. The other is that all of this pretty much still leaves him in excellent shape. It's basically between him and a guy who a whole lot of people in the party don't trust on core Republican issues, and Perry has still survived a decade in office with surprisingly little baggage that will bring veto attempts from key GOP actors. There are some things that would make them look twice, whether it's immigration or immunization or property rights (which I assume we'll hear about soon), but really: are any people who care passionately about abortion in the GOP going to choose Romney over Perry? Nope.
I've been very hesitant to hazard a prediction between the viable candidates, and I'm not going to start now. What I'll say is that with the combined Intrade odds still scraping 70%, the combination of Romney and Perry remains massively underpriced there (although I believe some of that is the mechanics of their market). And that at this point, I'd still pay a lot more attention to public endorsements and other indications of party actor support than I would to polling of regular voters. Remember, most ordinary voters -- even those plugged in enough to vote in primaries -- aren't really paying very much attention to this yet.