Flexible response

Flexible response was a defense strategy implemented by John F. Kennedy in 1961 to address the Kennedy administration's skepticism of Dwight Eisenhower's New Look and its policy of massive retaliation. Flexible response calls for mutual deterrence at strategic, tactical, and conventional levels, giving the United States the capability to respond to aggression across the spectrum of warfare, not limited only to nuclear arms.

The New Look policy, though initially useful, quickly became obsolete with the introduction of inter-continental delivery systems that undermined the credibility of a deterrence threat. The cornerstone of U.S. and European defense strategy was then threatened as the U.S. could no longer rely on nuclear threats to provide security for it and its allies.

John F. Kennedy won the presidency by claiming that the Republican Party had allowed the U.S. to fall behind the Soviets into a missile gap. Upon entering office Kennedy cited General Maxwell Taylor's book The Uncertain Trumpet to Congress for its conclusion that massive retaliation left the U.S. with only two choices: defeat on the ground or the resort to the use of nuclear weapons. Technology had improved since massive retaliation was adopted. Improvements in communication and transportation meant U.S. forces could be deployed more effectively, quickly, and flexibly than before. Advisers persuaded Kennedy that having multiple options would allow the president to apply the appropriate amount of force at the right place without risking escalation or losing alternatives. This would improve credibility for deterrence as the U.S. would now have low-intensity options and therefore would be more likely to use them, rather than massive retaliation's all-or-nothing options.

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