Greg Sargent notices something interesting in the PPP poll showing how unhinged GOP primary voters are on the question of Obama's very legitimacy as president: among non-Birthers, Sarah Palin has a favorable/unfavorable rating of 41 - 52. Among Birthers, it's a whoppingly favorable 83 - 12, far higher than anyone else. Here's Greg's interpretation: It seems fair to speculate that the success of Palin's approach -- her grievance-mongering, her strident attacks on Obama, her virtuosity in crafting the most lurid formulations to paint Obama as an alternately weak and tyrannical figure -- is rooted in her unique ability to speak...