Extended Deterrence

The idea of extended deterrence is for one actor (A), normally a state, to provide for the security of another (B) by threatening to punish another actor (C) should C undertake a particular course of action against B. The concept is therefore focused on the deterrent concept of punishment rather than denial. At the very heart of the concept of extended deterrence lies the issue of credibility—is another actor prepared to act on behalf of a third party? If the answer is yes, then extended deterrence can work; if the answer is no, then extended deterrence automatically fails. The question is whether actor C believes the threats being made by actor A to protect B.

Extended deterrence has been an element within the international system from its beginning. For example, after the annexation of Czechoslovakia by Germany in 1939, the British and French governments attempted to use extended deterrence as a mechanism to protect Poland from German advances, but this failed, with German forces invading Poland on September 1, 1939.

Nevertheless, the concept of extended deterrence is most closely associated with the North Atlantic Treaty Organization (NATO). Article V of the Washington Treaty, which formed NATO, stated, “An armed attack against one or more of them in Europe or North America shall be considered an attack against them all …” In reality, this meant that the dominant member—the United States—provided a conventional and ultimately a nuclear guarantee against the threat posed by the Soviet Union during the cold war. The U.S. nuclear provision allowed a number of NATO members to abandon their own nuclear programs and concentrate on providing for their conventional defense.

Although the United States had either a monopoly on the possession of nuclear weapons or the ability to strike the Soviet Union without a requisite response against the United States itself, the guarantee was seen by many to be secure. However, with the development of a Soviet capacity to strike the United States from the late 1950s on, the policy became increasingly questioned, especially once the United States and Soviet Union reached the point of mutually assured destruction. In the language of the 1970s debate, would a U.S. president be prepared to sacrifice Washington or New York to save London or Paris? Many thought not but no war resulted, and the United States officially continues to provide a nuclear guarantee to the rest of NATO.

Interestingly, the British government used these doubts about the U.S. nuclear guarantee as one of the justifications for the maintenance of its own nuclear deterrent, with references made to the importance of a second center for decision making (i.e., not just the United States) as a mechanism for reinforcing the concept of extended deterrence.

Extended deterrence is not solely a NATO concept or one that revolves only around the threatened use of nuclear weapons. The United States has consistently provided protection for a number of other states during the cold war and even today, such as South Korea, Japan, and Taiwan. In the case of the first two, this involves the permanent [Page 237]stationing of U.S. forces in those countries as a sign of the U.S. commitment to their defense. In the case of Taiwan, the United States has signaled its support through the sale of arms and the periodic deployment of aircraft carriers near to Taiwan during times of heightened tension between Taiwan and mainland China including, at times, sailing such carrier battle groups directly between Taiwan and the Chinese mainland.

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