This struck me as relevant:

"If we desire to defeat the enemy, we must proportion our efforts to his powers of resistance. This is expressed by the power of two factors which cannot be separated, namely, the sum of available means and the strength of the Will."

Carl Von Clausewitz, On War, Chapter 1, Section 5. Utmost Exertion of Powers

(I'm still planning on putting together a post of game theory, war, and morality, but I think most of you will be inclined to disagree with my conclusions, so I'm really doing my homework for this one.)