The American relationship with Israel is both a political and an intellectual challenge for some students of foreign affairs.  Convinced that US national interests would be best served by distancing ourselves from the Jewish state, scholars try to figure out why our country behaves in this seemingly self-defeating way. The problem is particularly tough for hard core realists who believe that the behavior of every state is determined by the nature of the international system.  For these thinkers, domestic politics don't matter; states do what they must. States are like billiard balls; they move when struck.  It doesn't matter what the...