Can Political Opponent Use Cake Throwing Photo?

Dear Rich: I have a question related to misuse of a photo from a personal profile on Facebook. I have a friend who is running for a public official seat. Someone took pictures of my friend in a party where someone throws a cake on his face. His opponent used this photo in a political ad in another context. Does my friend have a case of invasion of privacy, copyright infringement or defamation? It's not likely to be defamation. You're defamed when someone makes an untrue statement that injures your reputation ... and we're not sure that a face full of frosting ruins a politician's reputation. Politics is a contact sport and free speech reigns supreme. It's also probably not an invasion of privacy unless perhaps the photographer was trespassing at the cake-throwing event.
Copyright. If the photograph was reproduced without authorization, the opponent may have committed copyright infringement. The copyright owner -- probably the photographer -- could bring that claim (not your friend). Copyright lawsuits in political campaigns are used strategically, or to distance a copyright owner from a candidate. Some political infringements are excused as a fair use and most are resolved long after the campaign has ended.