Taibbi gets it exactly right, I think:

She is the country’s first WWE politician — a cartoon combatant who inspires stadiums full of frustrated middle American followers who will cheer for her against whichever villain they trot out, be it Newsweek, Barack Obama, Katie Couric, Steve Schmidt, the Mad Russian, Randy Orton or whoever. Her followers will not know that she is the perfect patsy for our system, designed as it is to channel popular anger in any direction but a useful one, and to keep the public tied up endlessly in pointless media melees over meaningless nonsense (melees of the sort that develop organically around Palin everywhere she goes). Like George W. Bush, even Palin herself doesn’t know this, another reason she’s such a perfect political tool.