While the threat of all-out punishment may lose credibility with the achievement of invulnerability by both sides’ retaliatory forces, the threat of limited retaliation may well gain it. Whatever the net effect, we cannot deprecate a world of invulnerable SAC’s simply by reference to the need for third-area deterrence; it has to be demonstrated that one particular deterrent threat (the massive one) is more potent than the other (limited) one.

DEFINE: Distinguishes between massive and limited retaliation as distinct deterrence mechanisms whose credibility shifts with force invulnerability. Builds on: "Limited retaliation gains credibility as all-out strike risks diminish."

Thomas C. Schelling, The Strategy of Conflict, loc. 587