Superior problem-solving mechanisms, though, are not in themselves enough to win wars. For that, as well as intelligence, you need superior resources and stamina — in short, brute force. Kennedy is right to say that only a multi-causal explanation can answer the question of why the Allies won. He perhaps underplays the role of might in deciding on the outcome. Of all the elements in the defeat of Hitler, the most important was the latent strength of the Soviet Union and its willingness to expend it in the endless blood-letting of the Eastern Front battles. It was there that the struggle was decided. And it was brute force rather than boffin-power that won the day.