Kagan is misguided – he bases theories on incomplete empirics and doesn’t acknowledge the controversial nature of his historical interpretations.

Such is Kagan’s thesis. What are we to think of it? First, his account of the origins of World War I and of American entry into the war is one-sided and in my view wrong. But more important for our present purpose, Kagan gives his readers no indication that what he says is controversial. In his discussion of the origins of World War I, he uncritically adopts Fritz Fischer’s thesis that the war came about as the result of a deliberate attempt by Germany to gain European hegemony. He mentions that a revisionist group of historians after the war challenged the Versailles verdict of unique German guilt, but he doesn’t tell us what their arguments were. He notes that Harry Elmer Barnes had churned out propaganda against the Kaiser during the war and changed his mind afterwards, disillusioned by what he regarded as Wilson’s betrayal of his idealistic principles, but Kagan does not tell us what Barnes said in his major revisionist study, The Genesis of the World War (1926), namely that Russia and France used the crisis after the assassination of Archduke Franz Ferdinand to bring about a general war in order to secure territorial gains to both countries.