In short, absolute, so-called mathematical, factors never find a firm basis in military calculations. From the very start, there is an interplay of possibilities, probabilities, good luck and bad, that weaves its way throughout the length and breadth of the tapestry. In the whole range of human activities, war most closely resembles a game of cards.

To be practical, any plan must take account of the enemy's power to frustrate it.

The object of defense is preservation; and since it is easier to hold ground than to take it, defense is easier than attack. But defense has a passive purpose: preservation; and attack a positive one: conquest.... If defense is the stronger form of war, yet has a negative object, it follows that it should be used only so long as weakness compels, and be abandoned as soon as we are strong enough to pursue a positive object.

Friction is the only concept that more or less corresponds to the factors that distinguish real war from war on paper.

Whoever does great things with small means has successfully reached the goal.

War is...a trinity of violence, chance, and reason.

What do we mean by the defeat of the enemy? Simply the destruction of his forces, whether by death, injury, or any other means-either completely or enough to make him stop fighting. . . . The complete or partial destruction of the enemy must be regarded as the sole object of all engagements. . . . Direct annihilation of the enemy's forces must always be the dominant consideration.