It is one of history's great "what ifs." What if Robert Kennedy had not been assassinated 40 years ago and gone on to become president of the United States? It's safe to say that his presidency would have followed a different course from that of Richard Nixon. And it may just be that American politics would not be endlessly refighting the 1960s. Kennedy was a less polarizing figure than Nixon, who exploited the divisions that have now hardened into Red States and Blue States. But Kennedy himself was a complex and mercurial figure, so all we can really do is speculate. It's an intriguing guessing game—if one does not get too dreamy about the mythology of RFK.