War is a mere continuation of policy by other means.Carl von Clausewitz
Even a cursory examination of typical behavior patterns under an all-or-nothing defense posture reveals the weakness of a policy that forgoes a tactical-level threat. The only remotely plausible deterrence equilibrium associated with all-or-nothing deployments requires that Challenger be Soft and likely unwilling to wage a high-level conflict. This, however, is the easier case. Relying exclusively on a threat to escalate is insufficient to deter Challenger when Challenger is likely Hard and, therefore, likely to respond, tit-for-tat, to any escalation.
It is no wonder, then, that the Eisenhower administration's deployment policy came under intense criticism among defense analysts almost as soon as it was announced. Critics asserted, prematurely it now appears (Gaddis, 1997), that the threat of Massive Retaliation lacked credibility (Kaufmann, 1956). And they claimed that the New Look, by stressing “more bang for the buck,” placed undue reliance on strategic weapons to deter Soviet aggression in Europe and elsewhere, leaving little room for maneuver during periods of acute crisis. To avoid the stark choice of either all-out nuclear war or capitulation, they proposed that United States conventional forces be strengthened, and augmented with an arsenal of tactical nuclear weapons (Kissinger, 1957b).
When the Democrats came to power in 1961, these changes were pursued under a policy labeled Flexible Response. In 1967, after extensive debate and compromise, NATO formally adopted Flexible Response (Stromseth, 1988).