The question I would ask is, "Why would a celebrity who wishes to appeal to a broad audience want to risk alienating part of that audience by endorsing a particular candidate?" It's one thing when a celebrity's reputation is based upon a particular set of social/political values (Michael Moore doesn't care if he alienates conservatives because they don't watch his films.), but another if one's art is politically neutral. There are probably a fair number of Obama supporters who will take a pass on Mr. Eastwood's next film because of his endorsement of Romney.