The first round of Perry vetting hasn’t laid a glove on Perry’s appeal to right-of-center voters. According to Public Policy Polling, Perry is in an incredibly strong position. He is the plurality first choice for GOP voters in a three way race against Bachmann and Romney. Perry is also the second choice for a majority of Romney and Bachmann voters. My read is that Bachmann supporters who are worried about conservative authenticity think of Perry as more authentic than Romney, and Romney voters who are worried about governing competence think that Perry is more competent than Bachmann. The incentives are for Romney and Bachmann to ignore each other and focus on destroying Perry (they would both benefit from a two way Romney-Bachmann contest.) I have no idea how they would go about doing that.
