In fact, what we are dealing with in the analysis of limited war is tradition. We are dealing with precedent, convention, and the force of suggestion. We are dealing with the theory of unwritten law—with conventions whose sanction in the aggregate is the need for mutual forbearance to avoid mutual destruction, and whose sanction in each individual case is the risk that to breach a rule may collapse it and that to collapse it may lead to a jointly less favorable limit or to none at all, and may further weaken the yet unbroken rules by providing evidence that their “authority” cannot be taken for granted.

Thomas C. Schelling, The Strategy of Conflict, loc. 596