The military art is not an accomplishment, an art for dilettante, a sport. You do not make war without reason, without an object, as you would give yourself up to music, painting, hunting, lawn tennis, where there is no great harm done whether you stop altogether or go on, whether you do little or much. Everything in war is linked together, is mutually interdependent, mutually interpenetrating. When you are at war you have no power to act at random. Each operation has a raison d'etre, that is an object; that object, once determined, fixes the nature and the value of the means to be resorted to as well as the use which ought to be made of the forces.

p. 214 - Precepts and Judgments (1919)