Carl von Clausewitz (1780-1831), the Prussian military theoretician who wrote On War, is known above all for his famous dictum: "War is the continuation of politics by other means." In Ren Girard's view, however, the strategist's treatise offers up a more disturbing truth to the reader willing to extrapolate from its most daring observations: with modern warfare comes the insanity of tit-for-tat escalation, which political institutions...