Collision being about as mutual as anything can be, and often the only thing that one can threaten, the maneuvers by which one conveys a threat of mutual damage to another driver aggressing on one’s right of way are an instructive example of the kind of threat that is conveyed not by words but by actions, and of the threat in which the pledge to fulfill is made not by verbal announcement but by losing the power to do otherwise.

DEFINE: Distinguishes credible threats that are communicated through action—committing so fully that one loses the ability to back down—from verbal threats.

Thomas C. Schelling, The Strategy of Conflict, loc. 34