So who is pulling Obama's strings?
The question assumes that Obama's strings are being pulled. Recall, please that he was nominated as a result of the voters selecting him in a long series of primaries. So you could say that the voters put him where he is through a deocratic process. He seems to be pulling his own strings with regard to issues.
Not so Palin, who was selected by just one person--John McCain, and was then sequestered and prevented from saying anything to anyone by the handlers appointed by McCain. Like Isabel Peron, she owes her national fame to only McCain, and her own ambition, since she took an oath of office to serve a term as Alaska's governor, which she wil not be able to fulfill if elected VP. Essentially she was chosen to prove that McCain, who is only occasionally in disagreement with the inept GOP bureaucracy, is in fact a "Maverick", an unbranded steer separated from the herd, to cause the base of the Party, who dislike McCain for not rubberstamping all of Juniorbush's decisions because she has bnoneheaded stands on rightwing cultural issues like abortion and religion, and to woo women who liked Hillary more for her gender than her abilities and her beliefs.