The esteemed Yale historian Paul Kennedy thinks there is something missing from what we talk about when we talk about how the Allies won World War II. Much has been written about the generals, the grunts, and the leaders — FDR, Stalin, Churchill — who formulated the strategies to defeat the Axis powers. But victory, however much it may seem so in retrospect, was hardly assured or inevitable.

For Kennedy, best known for his 1987 book, “The Rise and Fall of the Great Powers,’’ and his theories about imperial overstretch, it is not good enough to say that the combined industrial and military might of the United States, the British Empire, and the Soviet Union delivered a knockout blow to Germany and Japan. Kennedy frowns on single causes or turning points — like Stalingrad — to explain the defeat of Germany. He pooh-poohs any attempt to chalk up victory to a particular weapon or service or commander, whether the Royal Air Force or the US Marine Corps or Patton.