Flexible Response. The doctrine of “flexible response” was a not entirely successful attempt to “square the circle” of nuclear weapons strategy by suggesting ways in which nuclear weapons could be used, together with conventional weapons, in battle without invoking nuclear Armageddon. Though it remains a part of official U.S. policy in the 1990s, it has been eclipsed by increasing awareness that nuclear weapons have no utility except to deter others from using these weapons.

The phrase was widely publicized by Gen. Maxwell Taylor in his book The Uncertain Trumpet (1960) published immediately after his resignation as chief of staff of the U.S. Army in protest to army budget cuts. Taylor argued that the doctrine of “massive retaliation” had been overtaken by events because of the growing Soviet nuclear capability, and that nuclear weapons, or at least strategic as distinguished from tactical nuclear weapons, by themselves did not constitute an effective response to low‐level aggression. Taylor proposed a significant expansion of conventional weapons budgets and troop strength, which had been cut back during his term as chief of staff, with consequent losses to the army in its battles with the other services over the division of the military budget.

Taylor's ideas were enthusiastically adopted by the Kennedy administration, and President John F. Kennedy appointed him a special adviser, and then chairman of the Joint Chiefs of Staff (1962). Kennedy had already expressed the view, in a major speech on the Senate floor in 1960, that U.S. nuclear retaliatory power “cannot deter Communist aggression” and was “too limited to justify atomic war,” although he did not refer to the doctrine of flexible response by name.

One of the first official acts of Secretary of Defense Robert S. McNamara was to instruct the Joint Chiefs to revise the Single Integrated Operating Plan (SIOP) to create several options for the use of the strategic nuclear force, in place of the single option of ordering a devastating attack on Soviet society. At the same time, McNamara sought and obtained from the Congress substantial increases in funding for nonnuclear forces. These increases were designed to assure that the NATO conventional response to a Soviet incursion across the Iron Curtain would be more than token resistance designed to trigger the employment of nuclear weapons, despite European nervousness that anything more than a conventional trigger might weaken the effectiveness of the nuclear deterrent. In a special presidential message of 28 March 1961 accompanying the major budget revisions, Kennedy asserted: “Our defense posture must be both flexible and determined … our response … selective, permitting deliberation and discrimination as to timing, scope and targets …”

Reacting in part to Nikita Khrushchev's call for “wars of national liberation,” the Kennedy administration made training for “sub‐limited war” a key element in its flexible response policy, including special emphasis on counterinsurgency by special operations forces such as the army's Green Beret teams.

Early theorists of nuclear strategy, like Bernard Brodie and William Kaufmann, rejecting massive retaliation except as an instrument of last resort, embraced policies that could be described as flexible response, although again they did not employ the term. Brodie for a time explored the potential of tactical nuclear weapons as offering more flexibility. Others, particularly Herman Kahn, argued that the United States could survive a major nuclear exchange, provided it undertook an extensive civil defense effort.

McNamara, applying the doctrine in practice, realized that it did not offer a ready answer to the fundamental question, How much is enough? At first he proposed, in a speech to NATO allies later delivered in unclassified form at the University of Michigan, that strategic nuclear forces should be configured like conventional forces, “to destroy the enemy's military forces, not his civilian population.” This proposal was motivated in part by the desire to constrain allied, and particularly French, nuclear forces to coordinate their war plans, in order to reduce the likelihood that uncoordinated strikes would lead rapidly to nuclear Armageddon.

McNamara later shifted his emphasis away from a counterforce strategy to base his nuclear force requirements on the capacity to inflict unacceptable damage on the enemy (i.e., Soviet) society and economy, after absorbing the most powerful first strike that could be directed against the United States. This doctrine of Mutual Assured Destruction (derisively labeled MAD by its critics) did not exclude the possibility of flexible response, including limited nuclear response to a Soviet conventional attack across the North German plain, relying on nuclear weapons to overcome an assumed Soviet conventional superiority. But MAD supporters put more faith in an assured second‐strike capability than in the threat of limited nuclear weapons involvement, which could too easily escalate into an all‐out nuclear exchange. President Richard M. Nixon's substitution of “sufficiency” for “supremacy” in the vocabulary of nuclear strength made Mutual Assured Destruction more palatable.

A flexible response analysis (not under that name) had a brief revival in the 1980s when the Soviets initiated the deployment of a new nuclear‐tipped missile specifically aimed at European targets, and NATO responded by beginning the deployment of two Europe‐based missiles targeted on the Soviet Union, generating a major controversy in Europe and the United States over the appropriateness of the response. But Premier Mikhail Gorbachev resolved the controversy by accepting an earlier proposal by President Ronald Reagan to terminate both deployments.

It can be argued that the shift from massive retaliation to flexible response created a more favorable climate for arms control negotiations. It seems more logical, however, to attribute both developments to the realization that eventual rough nuclear parity with the Soviets was inevitable—and rough parity was good enough to produce mutual assured destruction.

On the debit side, critics of U.S. involvement in the Vietnam War (e.g., Brodie) argue that the idea of flexible response may have helped to lead the United States into the Vietnamese quagmire, and, as Colin Grey has observed, “Strategic concepts of flexible response and controlled escalation have … tended to blind decision makers to the possible employment of non‐military options.”

Bibliography

William W. Kaufmann, ed., Military Policy and National Security, 1956.
Maxwell D. Taylor , The Uncertain Trumpet, 1960.
William W. Kaufmann , The McNamara Strategy, 1964.
John Newhouse , et al., U.S. Troops in Europe, 1971.
Bernard Brodie , War and Politics, 1973.
Colin S. Gray , Strategic Studies and Public Policy: The American Experience, 1982.
Robert Jervis , The Illogic of American Nuclear Strategy, 1984.
James Woolsey, ed., Nuclear Arms: Ethics, Strategy, Politics, 1984.
Gregg Herken , Counsels of War, expanded ed., 1987.
McGeorge Bundy , Danger and Survival, 1988.

Adam Yarmolinsky