That's how Seth Mandel reads the polling:
In the most recent Gallup polling, Perry’s positive intensity score is at 23, five points higher than Palin’s 18. The full poll, however, shows when Perry and Palin are in the race together, Perry polls at 15 percent to Palin’s 12. (The poll includes Rudy Giuliani as well.) Additionally, Perry has the kind of grassroots support, popularity with conservative new media and solid reputation among conservative evangelical voters from which Palin would build a campaign. For Palin to run, she would need to focus her firepower on a moderate establishment candidate, like Romney. But Perry may well begin his official campaign as either the frontrunner or close to it.
There's no doubt they compete for the same electorate. But in a battle for the true believers, my money is on Palin. And she is the incumbent vice-presidential candidate.
The Dish 