His high poll numbers nationally among Republicans reflect a general disastifaction with the GOP field.
Once Perry is subjected to less than partisan scrutiny, i get the feeling the shine will wear off very quickly. If he somehow wins the nomination, he will be compared constantly to Bush by the Obama camp. Having a living, breathing embodiment of GWBush to run against will be helpful to Obama's chances.
I don't know if "filling a vacuum" in the GOP field is a true path to success in a general election. We will see.
Of course i could be utterly completely wrong, i apparently was wrong in predicting he wouldn't get in just days ago.