Deterrence theory is the scholarship and practice of how threats of using force by one party can convince another party to refrain from initiating some other course of action. The central problem of deterrence revolves around how to credibly threaten military action or nuclear punishment on the adversary despite its costs to the deterrer. Deterrence in an international relations context is the application of deterrence theory to avoid conflict.
Deterrence is widely defined as any use of threats (implicit or explicit) or limited force intended to dissuade an actor from taking an action (i.e. maintain the status quo). Deterrence is unlike compellence, which is the attempt to drive an actor (such as a state) to take an action (i.e. alter the status quo). Both are forms of coercion. Compellence has been characterized as harder to successfully implement than deterrence. Deterrence also tends to be distinguished from defense or the use of full force in wartime.
Deterrence is most likely to be successful when a prospective attacker believes that the probability of success is low and the costs of attack are high. Central problems of deterrence include the credible communication of threats and assurance. Deterrence does not necessarily require military superiority.
The topic gained increased prominence as a military strategy during the Cold War with regard to the use of nuclear weapons. It is related to but distinct from the concept of mutual assured destruction, according to which a full-scale nuclear attack on a power with second-strike capability would devastate both parties. The internationalization of deterrence, including via nuclear sharing and nuclear umbrellas, became a key strategy for states seeking to project power while mitigating direct conflict. Examples include the Cuban Missile Crisis and NATO Double-Track Decision.
"General deterrence" is considered successful when an actor who might otherwise take an action refrains from doing so due to the consequences that the deterrer is perceived likely to take. "Immediate deterrence" is considered successful when an actor seriously contemplating immediate military force or action refrains from doing so. Scholars distinguish between "extended deterrence" (the protection of allies) and "direct deterrence" (protection of oneself). Rational deterrence theory holds that an attacker will be deterred if they believe that:(Probability of deterrer carrying out deterrent threat × Costs if threat carried out) > (Probability of the attacker accomplishing the action × Benefits of the action)This model is frequently simplified in game-theoretic terms as:Costs × P(Costs) > Benefits × P(Benefits)
History
World War II During World War II, some historians have argued that deterrence prevented the Western Allies and Axis from extensive and direct chemical warfare with each other, as had been used in World War I. Nonetheless, Nazi Germany used chemical weapons during the Siege of Sevastopol, Siege of Odessa, and Battle of the Kerch Peninsula, while Imperial Japan frequently used chemical weapons against Chinese troops. Conversely, during the Nuremberg trials, Hermann Göring stated that initiating an exchange of chemical weapons during the Operation Overlord would have immobilized the Wehrmacht, which widely relied on horse-drawn transport, and a suitable gas mask for horses had not been designed.
Cold War
Concept While the concept of deterrence precedes the Cold War, it was during the Cold War that the concept evolved into a clearly articulated objective in strategic planning and diplomacy, with considerable analysis by scholars.
Most of the innovative work on deterrence theory occurred from the late 1940s to mid-1960s. Historically, scholarship on deterrence has tended to focus on nuclear deterrence. Since the end of the Cold War, there has been an extension of deterrence scholarship to areas that are not specifically about nuclear weapons.
NATO was founded in 1949 with deterring aggression as one of its goals.
A distinction is sometimes made between nuclear deterrence and "conventional deterrence."
The two most prominent deterrent strategies are "denial" (denying the attacker the benefits of attack) and "punishment" (inflicting costs on the attacker).
The lesson of Munich, where appeasement failed, has contributed to deterrence theory. In the words of scholars Fredrik Logevall and Kenneth Osgood, "Munich and appeasement have become among the dirtiest words in American politics, synonymous with naivete and weakness, and signifying a craven willingness to barter away the nation's vital interests for empty promises." They claimed that the success of U.S. foreign policy often depends upon a president withstanding "the inevitable charges of appeasement that accompany any decision to negotiate with hostile powers.
Examples In November 1945, General Curtis LeMay, who led American air raids on Japan during World War II, said in a speech to the Ohio Society of New York that since "No air attack, once it is launched, can be completely stopped", his country needed an air force that could immediately retaliate: "If we are prepared it may never come. It is not immediately conceivable that any nation will dare to attack us if we are prepared".
In pursuit of nuclear deterrence, the superpowers of the USSR and U.S. engaged in a nuclear arms race. Warheads themselves evolved from fission weapons to thermonuclear weapons, and were extensively miniaturized for both strategic and tactical use. Nuclear weapons delivery was equally important, such as the perceived bomber gap and missile gap. Deterrence was a primary factor in the ultimate proliferation of nuclear weapons to ten nations in total. Generally, this was the form of the threat perceived from a nearby recently nuclear-armed neighbor. In the case of the nuclear programs of Israel and South Africa, deterrence was against the threat of conventional attack.
Additionally, chemical weapons were a component of deterrence for both sides of the Cold War, and large stockpiles were maintained until their destruction began following the 1993 Chemical Weapons Convention. Offensive biological weapons programs were pursued by both countries in the first two decades of the Cold War, but the United States program was ended by president Richard Nixon in 1969.
Concept
The concept of deterrence can be defined as the use of threats in limited force by one party to convince another party to refrain from initiating some course of action. In Arms and Influence (1966), Schelling offers a broader definition of deterrence, as he defines it as "to prevent from action by fear of consequences." Glenn Snyder also offers a broad definition of deterrence, as he argues that deterrence involves both the threat of sanction and the promise of reward.
A threat serves as a deterrent to the extent that it convinces its target not to carry out the intended action because of the costs and losses that target would incur. In international security, a policy of deterrence generally refers to threats of military retaliation directed by the leaders of one state to the leaders of another in an attempt to prevent the other state from resorting to the use of military force in pursuit of its foreign policy goals.
As outlined by Huth, a policy of deterrence can fit into two broad categories: preventing an armed attack against a state's own territory (known as direct deterrence) or preventing an armed attack against another state (known as extended deterrence). Situations of direct deterrence often occur if there is a territorial dispute between neighboring states in which major powers like the United States do not directly intervene. On the other hand, situations of extended deterrence often occur when a great power becomes involved. The latter case has generated most interest in academic literature. Building on the two broad categories, Huth goes on to outline that deterrence policies may be implemented in response to a pressing short-term threat (known as immediate deterrence) or as strategy to prevent a military conflict or short-term threat from arising (known as general deterrence).
A successful deterrence policy must be considered in military terms but also political terms: International relations, foreign policy and diplomacy. In military terms, deterrence success refers to preventing state leaders from issuing military threats and actions that escalate peacetime diplomatic and military co-operation into a crisis or militarized confrontation that threatens armed conflict and possibly war.The prevention of crises of wars, however, is not the only aim of deterrence. In addition, defending states must be able to resist the political and the military demands of a potential attacking nation. If armed conflict is avoided at the price of diplomatic concessions to the maximum demands of the potential attacking nation under the threat of war, it cannot be claimed that deterrence has succeeded.
Furthermore, as Jentleson et al. argue, two key sets of factors for successful deterrence are important: a defending state strategy that balances credible coercion and deft diplomacy consistent with the three criteria of proportionality, reciprocity, and coercive credibility and minimizes international and domestic constraints and the extent of an attacking state's vulnerability as shaped by its domestic political and economic conditions. In broad terms, a state wishing to implement a strategy of deterrence is most likely to succeed if the costs of noncompliance that it can impose on and the benefits of compliance it can offer to another state are greater than the benefits of noncompliance and the costs of compliance.
Deterrence theory holds that nuclear weapons are intended to deter other states from attacking with their nuclear weapons, through the promise of retaliation and possibly mutually assured destruction. Nuclear deterrence can also be applied to an attack by conventional forces. For example, the doctrine of massive retaliation threatened to launch US nuclear weapons in response to Soviet attacks.
A successful nuclear deterrent requires a country to preserve its ability to retaliate by responding before its own weapons are destroyed or ensuring a second-strike capability. A nuclear deterrent is sometimes composed of a nuclear triad, as in the case of the nuclear weapons owned by the United States, Russia, China and India. Other countries, such as the United Kingdom and France, have only sea-based and air-based nuclear weapons.
Proportionality Jentleson et al. provides further detail in relation to those factors. Proportionality refers to the relationship between the defending state's scope and nature of the objectives being pursued and the instruments available for use to pursue them. The more the defending state demands of another state, the higher that state's costs of compliance and the greater need for the defending state's strategy to increase the costs of noncompliance and the benefits of compliance. That is a challenge, as deterrence is by definition a strategy of limited means. George (1991) goes on to explain that deterrence sometimes goes beyond threats to the actual use of military force, but if force is actually used, it must be limited and fall short of full-scale use to succeed.
The main source of disproportionality is an objective that goes beyond policy change to regime change, which has been seen in Libya, Iraq, and North Korea. There, defending states have sought to change the leadership of a state and to policy changes relating primarily to their nuclear weapons programs.
Reciprocity Secondly, Jentleson et al. outlines that reciprocity involves an explicit understanding of linkage between the defending state's carrots and the attacking state's concessions. The balance lies in not offering too little, too late or for too much in return and not offering too much, too soon, or for too little return.