Obamas position is very vulnerable right now. He has to tread a fine line between becoming a socialist, leftist and the moderate clintonesque rightist. It all takes just one major screw-up. It might be as simple as mishandling Iran (BTW, Iran was the Achilles heel for Carter and very well might be for Obama too). Once, people know there is a viable alternative in Sarah, they will desert him in droves. Then, it will be 1976 all over again
Vietnam>Nixon>Carter>Reagan = Iraq>Bush>Obama>Palin
War and unpopular presidents...