What makes atomic weapons different is a powerful tradition that they are different. The reason—in answer to the usual rhetorical question—why we do not ban bows and arrows on the grounds that they too, like nuclear weapons, kill and maim people, is that there is a tradition for the use of bows and arrows, a jointly recognized expectation that they will be used if it is expedient to use them. There is no such tradition for the use of atomic weapons. There is instead a tradition for their nonuse—a jointly recognized expectation that they may not be used in spite of declarations of readiness to use them, even in spite of tactical advantages in their use.

DEFINE: Introduces the concept of a 'tradition of nonuse' as the operative distinction for why atomic weapons are treated differently from conventional arms.

Thomas C. Schelling, The Strategy of Conflict, loc. 597