Deterrence

Deterrence is an exercise in coercion: it involves the use of threats and/or promises to dissuade an adversary from undertaking some action it might otherwise have taken. In political science terms, one entity, A, is said to have deterred another entity, B, if B, influenced by A's explicit or implicit threats or promises, chooses to refrain from certain activities. From A's perspective, deterrence represents an effort to achieve A's goal of preserving some aspect of the status quo by obtaining B's compliance, rather than by physically preventing an alteration in that status quo. From B's perspective, deterrence represents A's deliberate manipulation of B's calculation of costs and benefits to make acceptance of the status quo more attractive than challenging it.

For deterrence to operate, two conditions must exist. First, A must possess an effective coercive strategy—some combination of negative and positive sanctions large enough to shift B's evaluation of the desirability of a particular action. Negative sanctions for noncompliance may be of three sorts: denial of benefits; retaliation; or punishment. Second, A must be able credibly to commit itself to carrying out its effective coercive strategy. Because imposing negative or positive sanctions is unlikely to be cost‐free for A, A's capacity credibly to commit itself may be problematic. Credible commitment to threats and promises can be established in three ways: by taking steps, ex ante, to ensure that the costs of failing to carry out threats and promises exceed the costs of carrying them out; by arranging for the threats and promises to be carried out automatically (as in “Dr. Strangelove's” fictional doomsday machine); or by ensuring, ex ante, that decisions to execute sanctions will be made irrationally, without due attention to costs and benefits.

Though both are exercises in coercion, deterrence differs from compellence in what A demands of B. In deterrence, A seeks to convince B not to undertake particular actions. In compellence, A seeks to force B to undertake particular actions. The distinction is between coercion aimed at preserving the status quo and coercion aimed at changing it. Deterrence is likely to be easier to accomplish than compellence because deterrence does not involve a deadline for action and is less likely to involve a visible and humiliating act of compliance, and because, whereas deterrence simply maintains the status quo, in compellence it is unclear where A's demands will end once B begins to make concessions.

Deterrence and compellence both involve coercive uses of power by A to achieve its goals indirectly, by obtaining B's compliance. They differ from direct uses of power aimed at achieving A's desired outcome regardless of B's behavior. This difference yields the distinction between deterrence and defense. Deterrence aims to reduce or eliminate B's interest in undertaking certain actions, and its success rests on A's capacity credibly to commit itself to harm B. Defense aims to reduce or eliminate B's capacity to hurt A or A's interests: its success rests on A's capacity to disarm, defeat, or protect against B. A's ability to limit or eliminate B's physical capacity to impose pain on A is irrelevant to deterrence, but is the essential element of defense. Measures aimed at defense may be preemptive (that is, may involve destroying or neutralizing B's capabilities before B has an opportunity to use them); active (defeating, repulsing, or blunting B's actions); or passive (protecting items of value against the consequences of B's successful actions).

The distinction between deterrence and defense is evident in alternative Cold War strategies developed for dealing with the possibility of a Soviet nuclear attack. The Assured Destruction and Mutual Assured Destruction (MAD) doctrines enunciated by Secretary of Defense Robert S. McNamara, and the various strategies of controlled nuclear retaliation developed after the early 1960s, reflect the logic of deterrence: they acknowledged the vulnerability of American society to a Soviet attack, but aimed to protect the territory of the United States by credibly committing it to exact appropriate retribution. By contrast, active defenses like the proposed Sentinel thin area defense antiballistic missile (ABM) program of the late 1960s, or broad missile defenses like those envisioned in President Ronald Reagan's 1984 Strategic Defense Initiative (SDI), reflect the idea of defending against, rather than deterring, an attack.

Though deterrence has always coexisted with defense as an element in American military policy, the development by the end of World War II of effective long‐range airpower, missile technology, and atomic weapons simultaneously rendered defense more difficult and increased national capacity to threaten an adversary with massive suffering. Insightful observers like Bernard Brodie noted almost immediately the basic implications of these technological developments for American security policy. The Eisenhower administration's explicit incorporation of nuclear deterrence—“massive retaliation”—into U.S. defense planning in 1954 as part of its “New Look” in national security policy sharply accelerated the development of deterrence theory, principally by civilian analysts and scholars.

The early theorizing of the immediate postwar period was supplemented in the late 1950s and early 1960s by careful analyses by Brodie, Herman Kahn, William Kaufman, Klaus Knorr, Thomas Schelling, Glenn Snyder, and Albert Wohlstetter, among others, who explored the problems of achieving credible commitment, assuring “second‐strike” capability, enhancing stability in situations of mutual vulnerability, using threats of limited and controlled retaliation to make nuclear deterrence credible even while American cities remained hostage, and employing arms control to enhance crisis management and arms race stability. This theorizing provided the blueprint for American nuclear strategy and arms control policy from the mid‐1960s until the administration of Ronald Reagan. With SDI and particularly with the end of the Cold War, the focus of U.S. nuclear policy shifted increasingly from the problem of deterrence to the problems of defense against limited nuclear attacks, as well as nuclear proliferation.
[See also Arms Control and Disarmament; Game Theory; Missiles; Nuclear Weapons; Nuclear War, Prevention of Accidental; Strategy: Fundamentals; Strategy: Nuclear Warfare Strategy.]

Bibliography

Bernard Brodie , Strategy in the Missile Age, 1959.
Thomas C. Schelling , Arms and Influence, 1966.
Glenn H. Snyder , Deterrence and Defense, 1961.
Alexander L. George and and Richard Smoke , Deterrence in American Foreign Policy, 1974.
Robert Jervis , The Illogic of American Nuclear Strategy, 1984.
Edward Rhodes , Power and MADness: The Logic of Nuclear Coercion, 1989.
Ted Hopf , Peripheral Visions: Deterrence Theory and American Foreign Policy in the Third World, 1965–1990, 1994.

Edward Rhodes