Deterrence theory

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The USS Growler, one of two submarines designed to provide a nuclear deterrence using cruise missiles with a 500 miles (800 km) range—placed on patrol carrying the Regulus I missile (shown at Pier 86 in New York, its home as a museum ship).

 

Deterrence theory is the idea that an inferior force, by virtue of the destructive power of the force's weapons, could deter a more powerful adversary, provided that this force could be protected against destruction by a surprise attack. This doctrine gained increased prominence as a military strategy during the Cold War with regard to the use of nuclear weapons and is related to, but distinct from, the concept of Mutual assured destruction, which models the preventative nature of full-scale nuclear attack that would devastate both parties in a nuclear war. Deterrence is a strategy intended to dissuade an adversary from taking an action not yet started by means of threat of reprisal, or to prevent them from doing something that another state desires. The strategy is based on the psychological concept of the same name. A credible nuclear deterrent, Bernard Brodie wrote in 1959, must be always at the ready, yet never used.

In Thomas Schelling's (1966) classic work on deterrence, the concept that military strategy can no longer be defined as the science of military victory is presented. Instead, it is argued that military strategy was now equally, if not more, the art of coercion, of intimidation and deterrence.^[3] Schelling says the capacity to harm another state is now used as a motivating factor for other states to avoid it and influence another state's behavior. To be coercive or deter another state, violence must be anticipated and avoidable by accommodation. It can therefore be summarized that the use of the power to hurt as bargaining power is the foundation of deterrence theory, and is most successful when it is held in reserve.

In 2004 Frank C. Zagare made the case that deterrence theory is logically inconsistent, not empirically accurate, and that it is deficient as a theory. In place of classical deterrence, rational choice scholars have argued for perfect deterrence, which assumes that states may vary in their internal characteristics and especially in the credibility of their threats of retaliation.

In a January 2007 article in the Wall Street Journal, veteran cold-war policy makers Henry Kissinger, Bill Perry, George Shultz, and Sam Nunn reversed their previous position and asserted that far from making the world safer, nuclear weapons had become a source of extreme risk. Their rationale and conclusion was not based on the old world with only a few nuclear players, but on the instability in many states possessing the technologies and the lack of wherewithal to properly maintain and upgrade existing weapons in many states:

The risk of accidents, misjudgments or unauthorised launches, they argued, was growing more acute in a world of rivalries between relatively new nuclear states that lacked the security safeguards developed over many years by America and the Soviet Union. The emergence of pariah states, such as North Korea (possibly soon to be joined by Iran), armed with nuclear weapons was adding to the fear as was the declared ambition of terrorists to steal, buy or build a nuclear device.

— The Economist, June 16, 2011

According to The Economist, "Senior European statesmen and women" called for further action in 2010 in addressing problems of nuclear weapons proliferation. They said: "Nuclear deterrence is a far less persuasive strategic response to a world of potential regional nuclear arms races and nuclear terrorism than it was to the cold war".

Concept

The use of military threats as a means to deter international crises and war has been a central topic of international security research for at least 200 years. Research has predominantly focused on the theory of rational deterrence to analyze the conditions under which conventional deterrence is likely to succeed or fail. Alternative theories however have challenged the rational deterrence theory and have focused on organizational theory and cognitive psychology.

The concept of deterrence can be defined as the use of threats by one party to convince another party to refrain from initiating some course of action. 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 threat of 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 being (i) preventing an armed attack against a state's own territory (known as direct deterrence); or (ii) preventing an armed attack against another state (known as extended deterrence). Situations of direct deterrence often occur when 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. It is the latter that has generated the majority of interest in academic literature. Building on these 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 not only military terms, but also in political terms; specifically International Relations (IR), 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 cooperation into a crisis or militarized confrontation which 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 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, then it cannot be claimed that deterrence has succeeded.

Furthermore, as Jentleson et al. argue, two key sets of factors for successful deterrence are important being (i) a defending state strategy that firstly balances credible coercion and deft diplomacy consistent with the three criteria of proportionality, reciprocity, and coercive credibility, and secondly minimizes international and domestic constraints; and (ii) 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 non-compliance 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 (MAD). 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 that a country preserve its ability to retaliate, either by responding before its own weapons are destroyed or by 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, the People's Republic of China and India. Other countries, such as the United Kingdom and France, have only sea- and air-based nuclear weapons.

Proportionality

Jentleson et al. provide further detail in relation to these factors. Firstly, 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 this. 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. This is a challenge, as deterrence is, by definition, a strategy of limited means. George (1991) goes on to explain that deterrence may, but is not required to, go 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 or war otherwise it fails. The main source of disproportionality is an objective that goes beyond policy change to regime change. This has been seen in the cases of Libya, Iraq, and North Korea where defending states have sought to change the leadership of a state in addition to policy changes relating primarily to their nuclear weapons programs.

Reciprocity

Secondly, Jentleson et al. outline that reciprocity involves an explicit understanding of linkage between the defending state's carrots and the attacking state's concessions. The balance lies neither in offering too little too late or for too much in return, not offering too much too soon or for too little return.

Coercive credibility

Finally, coercive credibility requires that, in addition to calculations about costs and benefits of cooperation, the defending state convincingly conveys to the attacking state that non-cooperation has consequences. Threats, uses of force, and other coercive instruments such as economic sanctions must be sufficiently credible to raise the attacking state's perceived costs of noncompliance. A defending state having a superior military capability or economic strength in itself is not enough to ensure credibility. Indeed, all three elements of a balanced deterrence strategy are more likely to be achieved if other major international actors like the United Nations or NATO are supportive and if opposition within the defending state's domestic politics is limited. 

The other important consideration outlined by Jentleson et al. that must be taken into consideration is the domestic political and economic conditions within the attacking state affecting its vulnerability to deterrence policies, and the attacking state's ability to compensate unfavourable power balances. The first factor is whether internal political support and regime security are better served by defiance, or if there are domestic political gains to be made from improving relations with the defending state. The second factor is an economic calculation of the costs that military force, sanctions, and other coercive instruments can impose, and the benefits that trade and other economic incentives may carry. This in part is a function of the strength and flexibility of the attacking state's domestic economy and its capacity to absorb or counter the costs being imposed. The third factor is the role of elites and other key domestic political figures within the attacking state. To the extent these actors' interests are threatened with the defending state's demands, they act to prevent or block the defending state's demands.

Rational deterrence theory

The predominant approach to theorizing about deterrence has entailed the use of rational choice and game-theoretic models of decision making (see game theory). Deterrence theorists have consistently argued that deterrence success is more likely if a defending state's deterrent threat is credible to an attacking state. Huth outlines that a threat is considered credible if the defending state possesses both the military capabilities to inflict substantial costs on an attacking state in an armed conflict, and if the attacking state believes that the defending state is resolved to use its available military forces. Huth goes on to explain the four key factors for consideration under rational deterrence theory being (i) the military balance; (ii) signaling and bargaining power; (iii) reputations for resolve; and (iv) interests at stake.

The military balance

Deterrence is often directed against state leaders who have specific territorial goals that they seek to attain either by seizing disputed territory in a limited military attack or by occupying disputed territory after the decisive defeat of the adversary's armed forces. In either case, the strategic orientation of potential attacking states is generally short term and driven by concerns about military cost and effectiveness. For successful deterrence, defending states need the military capacity to respond quickly and in strength to a range of contingencies. Where deterrence often fails is when either a defending state or an attacking state under or overestimate the others' ability to undertake a particular course of action.

Signaling and bargaining power

The central problem for a state that seeks to communicate a credible deterrent threat through diplomatic or military actions is that all defending states have an incentive to act as if they are determined to resist an attack, in the hope that the attacking state will back away from military conflict with a seemingly resolved adversary. If all defending states have such incentives, then potential attacking states may discount statements made by defending states along with any movement of military forces as merely bluffs. In this regards, rational deterrence theorists have argued that costly signals are required to communicate the credibility of a defending state's resolve. Costly signals are those actions and statements that clearly increase the risk of a military conflict and also increase the costs of backing down from a deterrent threat. States that are bluffing are unwilling to cross a certain threshold of threat and military action for fear of committing themselves to an armed conflict.

Reputations for resolve

There are three different arguments that have been developed in relation to the role of reputations in influencing deterrence outcomes. The first argument focuses on a defending state's past behaviour in international disputes and crises, which creates strong beliefs in a potential attacking state about the defending state's expected behaviour in future conflicts. The credibilities of a defending state's policies are arguably linked over time, and reputations for resolve have a powerful causal impact on an attacking state's decision whether to challenge either general or immediate deterrence. The second approach argues that reputations have a limited impact on deterrence outcomes because the credibility of deterrence is heavily determined by the specific configuration of military capabilities, interests at stake, and political constraints faced by a defending state in a given situation of attempted deterrence. The argument of this school of thought is that potential attacking states are not likely to draw strong inferences about a defending states resolve from prior conflicts because potential attacking states do not believe that a defending state's past behaviour is a reliable predictor of future behaviour. The third approach is a middle ground between the first two approaches. It argues that potential attacking states are likely to draw reputational inferences about resolve from the past behaviour of defending states only under certain conditions. The insight is the expectation that decision makers will use only certain types of information when drawing inferences about reputations, and an attacking state updates and revises its beliefs when the unanticipated behaviour of a defending state cannot be explained by case-specific variables. An example both shows that the problem extends to the perception of the third parties as well as main adversaries and underlies the way in which attempts at deterrence can not only fail but backfire if the assumptions about the others' perceptions are incorrect.

Interests at stake

Although costly signaling and bargaining power are more well established arguments in rational deterrence theory, the interests of defending states are not as well known, and attacking states may look beyond the short term bargaining tactics of a defending state and seek to determine what interests are at stake for the defending state that would justify the risks of a military conflict. The argument here is that defending states that have greater interests at stake in a dispute are more resolved to use force and be more willing to endure military losses to secure those interests. Even less well established arguments are the specific interests that are more salient to state leaders such as military interests versus economic interests. 

Furthermore, Huth argues that both supporters and critics of rational deterrence theory agree that an unfavourable assessment of the domestic and international status quo by state leaders can undermine or severely test the success of deterrence. In a rational choice approach, if the expected utility of not using force is reduced by a declining status quo position, then deterrence failure is more likely, since the alternative option of using force becomes relatively more attractive.

Nuclear weapons and deterrence

In 1966 Schelling is prescriptive in outlining the impact of the development of nuclear weapons in the analysis of military power and deterrence. In his 1966 analysis, before the widespread use of assured second strike capability, or immediate reprisal, in the form of SSBN submarines, Schelling argues that nuclear weapons give nations the potential to not only destroy their enemies but humanity itself without drawing immediate reprisal because of the lack of a conceivable defense system and the speed with which nuclear weapons can be deployed. A nation's credible threat of such severe damage empowers their deterrence policies and fuels political coercion and military deadlock, which in turn can produce proxy warfare.

Historical analysis of nuclear weapons deterrent capabilities has led modern researchers to the concept of the stability-instability paradox, whereby nuclear weapons confer large scale stability between nuclear weapon states, as in over 60 years none have engaged in large direct warfare due primarily to nuclear weapons deterrence capabilities, but instead are forced into pursuing political aims by military means in the form of comparatively smaller scale acts of instability, such as proxy wars and minor conflicts.

Stages of the US policy of deterrence

The US policy of deterrence during the Cold War underwent significant variations.

Containment

The early stages of the Cold War were generally characterized by containment of communism, an aggressive stance on behalf of the US especially on developing nations under its sphere of influence. This period was characterized by numerous proxy wars throughout most of the globe, particularly Africa, Asia, Central America, and South America. A notable such conflict was the Korean War. George F. Kennan, who is taken to be the founder of this ideology in his Long Telegram, asserted that he never advocated military intervention, merely economic support; and that his ideas were misinterpreted when espoused by the general public.

Détente

With the U.S. drawdown from Vietnam, the normalization of U.S. relations with China, and the Sino-Soviet Split, the policy of Containment was abandoned and a new policy of détente was established, whereby peaceful coexistence was sought between the United States and the Soviet Union. Although all factors listed above contributed to this shift, the most important factor was probably the rough parity achieved in stockpiling nuclear weapons with the clear capability of Mutual Assured Destruction (MAD). Therefore, the period of détente was characterized by a general reduction in the tension between the Soviet Union and the United States and a thawing of the Cold War, lasting from the late 1960s until the start of the 1980s. The doctrine of mutual nuclear deterrence characterized relations between the United States and the Soviet Union during this period, and relations with Russia until the onset of the New Cold War in the early 2010s. Since then, the relations have been less clear.

Reagan era

A third shift occurred with President Ronald Reagan's arms build-up during the 1980s. Reagan attempted to justify this policy in part due to concerns of growing Soviet influence in Latin America and the new republic of Iran, established after the Iranian Revolution of 1979. Similar to the old policy of containment, the United States funded several proxy wars, including support for Saddam Hussein of Iraq during the Iran–Iraq War, support for the mujahideen in Afghanistan, who were fighting for independence from the Soviet Union, and several anti-communist movements in Latin America such as the overthrow of the Sandinista government in Nicaragua. The funding of the Contras in Nicaragua led to the Iran-Contra Affair, while overt support led to a ruling from the International Court of Justice against the United States in Nicaragua v. United States. 

While the army was dealing with the breakup of the Soviet Union and the spread of nuclear technology to other nations beyond the United States and Russia, the concept of deterrence took on a broader multinational dimension. The U.S. policy on post–Cold War deterrence was outlined in 1995 in a document called "Essentials of Post–Cold War Deterrence". This document explains that while relations with Russia continue to follow the traditional characteristics of Mutual Nuclear Deterrence, due to both nations continuing MAD, U.S. policy of deterrence towards nations with minor nuclear capabilities should ensure through threats of immense retaliation (or even preemptive action) that they do not threaten the United States, its interests, or allies. The document explains that such threats must also be used to ensure that nations without nuclear technology refrain from developing nuclear weapons and that a universal ban precludes any nation from maintaining chemical or biological weapons. The current tensions with Iran and North Korea over their nuclear programs are due in part to the continuation of this policy of deterrence.

Modern Deterrence

Modern Deterrence is the application of deterrence theory to non-nuclear and post-nuclear challenges, including hybrid warfare. As with nuclear deterrence, the aim of modern deterrence is to "dissuade an adversary from taking aggressive action by persuading that actor that the costs would outweigh the potential gains." However, the unattributable nature of some new forms of attacks, including propaganda and cyber attacks, and the fact that they may be below the threshold of an armed response pose a particular challenge for deterrence. CSIS have concluded that modern deterrence is made most effective at reducing the threat of non-nuclear attacks by:

• Establishing norms of behavior;
• Tailoring deterrence threats to individual actors;
• Adopting an all of government and society response; and
• Building credibility with adversaries, for example by always following through on threats.

Criticism

Deterrence theory is criticized for its assumptions about opponent rationales. 

First, it is argued that suicidal or psychotic opponents may not be deterred by either forms of deterrence. Second, if two enemy states both possess nuclear weapons, Country X may try to gain a first-strike advantage by suddenly launching weapons at Country Y, with a view to destroying its enemy's nuclear launch silos thereby rendering Country Y incapable of a response. Third, diplomatic misunderstandings and/or opposing political ideologies may lead to escalating mutual perceptions of threat, and a subsequent arms race that elevates the risk of actual war, a scenario illustrated in the movies WarGames (1983) and Dr. Strangelove (1964). An arms race is inefficient in its optimal output, as all countries involved expend resources on armaments that would not have been created if the others had not expended resources, a form of positive feedback. Fourth, escalation of perceived threat can make it easier for certain measures to be inflicted on a population by its government, such as restrictions on civil liberties, the creation of a military–industrial complex, and military expenditures resulting in higher taxes and increasing budget deficits. 

In recent years, many mainstream politicians, academic analysts, and retired military leaders have also criticized deterrence and advocated nuclear disarmament. Sam Nunn, William Perry, Henry Kissinger, and George Shultz have all called upon governments to embrace the vision of a world free of nuclear weapons, and in three Wall Street Journal op-eds proposed an ambitious program of urgent steps to that end. The four have created the Nuclear Security Project to advance this agenda. Organisations such as Global Zero, an international non-partisan group of 300 world leaders dedicated to achieving nuclear disarmament, have also been established. In 2010, the four were featured in a documentary film entitled Nuclear Tipping Point. The film is a visual and historical depiction of the ideas laid forth in the Wall Street Journal op-eds and reinforces their commitment to a world without nuclear weapons and the steps that can be taken to reach that goal.

Former Secretary Kissinger puts the new danger, which cannot be addressed by deterrence, this way: "The classical notion of deterrence was that there was some consequences before which aggressors and evildoers would recoil. In a world of suicide bombers, that calculation doesn't operate in any comparable way." Shultz has said, "If you think of the people who are doing suicide attacks, and people like that get a nuclear weapon, they are almost by definition not deterrable".

As opposed to the extreme mutually assured destruction form of deterrence, the concept of minimum deterrence in which a state possesses no more nuclear weapons than is necessary to deter an adversary from attacking is presently the most common form of deterrence practiced by nuclear weapon states, such as China, India, Pakistan, Britain, and France. Pursuing minimal deterrence during arms negotiations between United States and Russia allows each state to make nuclear stockpile reductions without the state becoming vulnerable, however it has been noted that there comes a point where further reductions may be undesirable, once minimal deterrence is reached, as further reductions beyond this point increase a state's vulnerability and provide an incentive for an adversary to secretly expand its nuclear arsenal.

"Senior European statesmen and women" called for further action in addressing problems of nuclear weapons proliferation in 2010. They said: "Nuclear deterrence is a far less persuasive strategic response to a world of potential regional nuclear arms races and nuclear terrorism than it was to the cold war".

Paul Virilio has criticized nuclear deterrence as anachronistic in the age of information warfare since disinformation and kompromat are the current threats to suggestible populations. The wound inflicted on unsuspecting populations he calls an "integral accident":

The first deterrence, nuclear deterrence, is presently being superseded by the second deterrence: a type of deterrence based on what I call 'the information bomb' associated with the new weaponry of information and communications technologies. Thus, in the very near future, and I stress this important point, it will no longer be war that is the continuation of politics by other means, it will be what I have dubbed 'the integral accident' that is the continuation of politics by other means.

Former deputy defense secretary and strategic arms treaty negotiator Paul Nitze stated in a Washington Post op-ed in 1994 that nuclear weapons were obsolete in the "new world disorder" following the dissolution of the Soviet Union, and advocated reliance on precision guided munitions to secure a permanent military advantage over future adversaries.

Nuclear arms race

From Wikipedia, the free encyclopedia

 

United States and Soviet Union/Russia nuclear weapon stockpiles

 

The nuclear arms race was an arms race competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War. During this period, in addition to the American and Soviet nuclear stockpiles, other countries developed nuclear weapons, though none engaged in warhead production on nearly the same scale as the two superpowers.

World War II

The first nuclear weapon was created by the United States of America during the Second World War and was developed to be used against the Axis powers. Scientists of the Soviet Union were aware of the potential of nuclear weapons and had also been conducting research on the field.

The Soviet Union was not informed officially of the Manhattan Project until Stalin was briefed at the Potsdam Conference on July 24, 1945, by U.S. President Harry S. Truman, eight days after the first successful test of a nuclear weapon. Despite their wartime military alliance, the United States and Britain had not trusted the Soviets enough to keep knowledge of the Manhattan Project safe from German spies: there were also concerns that, as an ally, the Soviet Union would request and expect to receive technical details of the new weapon.

When President Truman informed Stalin of the weapons, he was surprised at how calmly Stalin reacted to the news and thought that Stalin had not understood what he had been told. Other members of the United States and British delegations who closely observed the exchange formed the same conclusion.

In fact Stalin had long been aware of the program, despite the Manhattan Project having a secret classification so high that, even as Vice President, Truman did not know about it or the development of the weapons (Truman was not informed until shortly after he became president). A ring of spies operating within the Manhattan Project, (including Klaus Fuchs and Theodore Hall) had kept Stalin well informed of American progress. They provided the Soviets with detailed designs of the implosion bomb and the hydrogen bomb. Fuchs' arrest in 1950 led to the arrests of many other suspected Russian spies, including Harry Gold, David Greenglass, and Ethel and Julius Rosenberg.

In August 1945, on Truman's orders, two atomic bombs were dropped on Japanese cities. The first bomb was dropped on Hiroshima, and the second bomb was dropped on Nagasaki by the B-29 bombers named Enola Gay and Bockscar respectively. 

Shortly after the end of the Second World War in 1945, the United Nations was founded. During the United Nation's first General Assembly in London in January 1946, they discussed the future of Nuclear Weapons and created the United Nations Atomic Energy Commission. The goal of this assembly was to eliminate the use of all Nuclear weapons. The United States presented their solution, which was called the Baruch Plan. This plan proposed that there should be an international authority that controls all dangerous atomic activities. The Soviet Union disagreed with this proposal and rejected it. The Soviets' proposal involved universal nuclear disarmament. Both the American and Soviet proposals were refused by the UN.

Early Cold War

Warhead Development

In the years immediately after the Second World War, the United States had a monopoly on specific knowledge of and raw materials for nuclear weaponry. American leaders hoped that their exclusive ownership of nuclear weapons would be enough to draw concessions from the Soviet Union but this proved ineffective. 

Just six months after the UN General Assembly, the United States conducted its first post-war nuclear tests. This was called Operation Crossroads. The purpose of this operation was to test the effectiveness of nuclear explosions on ships. These tests were performed at Bikini Atoll in the Pacific on 95 ships, including German and Japanese ships that were captured during World War II. One plutonium implosion-type bomb was detonated over the fleet, while the other one was detonated underwater. 

Behind the scenes, the Soviet government was working on building its own atomic weapons. During the war, Soviet efforts had been limited by a lack of uranium but new supplies in Eastern Europe were found and provided a steady supply while the Soviets developed a domestic source. While American experts had predicted that the Soviet Union would not have nuclear weapons until the mid-1950s, the first Soviet bomb was detonated on August 29, 1949, shocking the entire world. The bomb, named "First Lightning" by the West, was more or less a copy of "Fat Man", one of the bombs the United States had dropped on Japan in 1945.

Both governments spent massive amounts to increase the quality and quantity of their nuclear arsenals. Both nations quickly began the development of a hydrogen bomb and the United States detonated the first hydrogen bomb on November 1, 1952, on Enewetak, an atoll in the Pacific Ocean. Code-named "Ivy Mike", the project was led by Edward Teller, a Hungarian-American nuclear physicist. It created a cloud 100 miles wide and 25 miles high, killing all life on the surrounding islands. Again, the Soviets surprised the world by exploding a deployable thermonuclear device in August 1953 although it was not a true multi-stage hydrogen bomb. However, it was small enough to be dropped from an airplane, making it ready for use. The development of these two Soviet bombs was greatly aided by the Russian spies Harry Gold and Klaus Fuchs.

On March 1, 1954, the U.S. conducted the Castle Bravo test, which tested another hydrogen bomb on Bikini Atoll. Scientists significantly underestimated the size of the bomb, thinking it would yield 5 megatons. However, it yielded 14.8 megatons, which is the largest nuclear explosion tested by the U.S. The explosion was so large the nuclear fallout exposed residents up to 300 miles away to significant amounts of radiation. They were eventually evacuated, but most of them experienced radiation poisoning and resulted in one death from a crew member of a fishing boat 90 miles from the explosion. 

The Soviet Union detonated its first "true" hydrogen bomb on November 22, 1955, which had a yield of 1.6 megatons. On October 30, 1961, the Soviets detonated a hydrogen bomb with a yield of approximately 58 megatons.

Arms Race

With both sides in the "cold war" having nuclear capability, an arms race developed, with the Soviet Union attempting first to catch up and then to surpass the Americans.

Russian Deputy Foreign Minister Sergey Ryabkov warned about a risk of nuclear war, as the negative dynamics was quite noticeable in 2018. He urged the nuclear states to build channels on forestalling potential incidents, in order to lower the risks.

Delivery Vehicles

Strategic bombers were the primary delivery method at the beginning of the Cold War.

Missiles had long been regarded the ideal platform for nuclear weapons, and were potentially a more effective delivery system than bombers. Starting in the 1950s, medium-range ballistic missiles and intermediate-range ballistic missiles ("IRBM"s) were developed for delivery of tactical nuclear weapons, and the technology developed to the progressively longer ranges, eventually becoming intercontinental ballistic missiles (ICBMs). On October 4, 1957, the Soviet Union showed the world that they had missiles able to reach any part of the world when they launched the Sputnik satellite into Earth orbit. The United States launched its first satellite Explorer 1 on January 31, 1958. 

Meanwhile, submarine-launched ballistic missiles were also developed. By the 1960s, the "triad" of nuclear weapon delivery was established, with each side deploying bombers, ICBMs, and SLBMs, in order to insure that even if a defense was found against one delivery method, the other methods would still be available.

Some in the United States during the early 1960s pointed out that although all of the individual components of nuclear missiles had been tested separately (warheads, navigation systems, rockets), it was infeasible to test them all combined. Critics charged that it was not really known how a warhead would react to the gravity forces and temperature differences encountered in the upper atmosphere and outer space, and Kennedy was unwilling to run a test of an ICBM with a live warhead. The closest thing to an actual test was 1962's Operation Frigate Bird, in which the submarine USS Ethan Allen (SSBN-608) launched a Polaris A2 missile over 1,000 miles to the nuclear test site at Christmas Island. It was challenged by, among others, Curtis LeMay, who put missile accuracy into doubt to encourage the development of new bombers. Other critics pointed out that it was a single test which could be an anomaly; that it was a lower-altitude SLBM and therefore was subject to different conditions than an ICBM; and that significant modifications had been made to its warhead before testing.

Mutual Assured Destruction (MAD)

By the 1950s both the United States and the Soviet Union had enough nuclear power to obliterate the other side. Both sides developed a capability to launch a devastating attack even after sustaining a full assault from the other side (especially by means of submarines), called a second strike. This policy became known as Mutual Assured Destruction: both sides knew that any attack upon the other would be devastating to themselves, thus in theory restraining them from attacking the other. 

Both Soviet and American experts hoped to use nuclear weapons for extracting concessions from the other, or from other powers such as China, but the risk connected with using these weapons was so grave that they refrained from what John Foster Dulles referred to as brinkmanship. While some, like General Douglas MacArthur, argued nuclear weapons should be used during the Korean War, both Truman and Eisenhower opposed the idea.

Both sides were unaware of the details of the capacity of the enemy's arsenal of nuclear weapons. The Americans suffered from a lack of confidence, and in the 1950s they believed in a non-existing bomber gap. Aerial photography later revealed that the Soviets had been playing a sort of Potemkin village game with their bombers in their military parades, flying them in large circles, making it appear they had far more than they truly did. The 1960 American presidential election saw accusations of a wholly spurious missile gap between the Soviets and the Americans. On the other side, the Soviet government exaggerated the power of Soviet weapons to the leadership and Nikita Khrushchev.

Initial nuclear proliferation

In addition to the United States and the Soviet Union, three other nations, the United Kingdom, People's Republic of China, and France developed nuclear weapons during the early cold war years. 

In 1952, the United Kingdom became the third nation to possess nuclear weapons when it detonated an atomic bomb in Operation Hurricane on October 3, 1952, which had a yield of 25 kilotons. Despite major contributions to the Manhattan Project by both Canadian and British governments, the U.S. Congress passed the Atomic Energy Act of 1946, which prohibited multi-national cooperation on nuclear projects. The Atomic Energy Act fueled resentment from British scientists and Winston Churchill, as they believed that there were agreements regarding post-war sharing of nuclear technology, and led to Britain developing its own nuclear weapons. Britain did not begin planning the development of their own nuclear weapon until January 1947. Because of Britain’s small size, they decided to test their bomb on the Monte Bello Islands, off the coast of Australia. Following this successful test, under the leadership of Churchill, Britain decided to develop and test a hydrogen bomb. The first successful hydrogen bomb test occurred on November 8, 1957, which had a yield of 1.8 megatons. An amendment to the Atomic Energy Act in 1958 allowed nuclear cooperation once again, and British-U.S. nuclear programs resumed. During the Cold War, British nuclear deterrence came from submarines and nuclear-armed aircraft. The Resolution class ballistic missile submarines armed with the American-built Polaris missile provided the sea deterrent, while aircraft such as the Avro Vulcan, SEPECAT Jaguar, Panavia Tornado and several other Royal Air Force strike aircraft carrying WE.177 gravity bomb provided the air deterrent.

France became the fourth nation to possess nuclear weapons on February 13, 1960, when the atomic bomb "Gerboise Bleue" was detonated in Algeria, then still a French colony [Formally a part of the Metropolitan France.] France began making plans for a nuclear-weapons program shortly after the Second World War, but the program did not actually begin until the late 1950s. Eight years later, France conducted its first thermonuclear test above Fangatuafa Atoll. It had a yield of 2.6 megatons. This bomb significantly contaminated the atoll with radiation for six years, making it off-limits to humans. During the Cold War, the French nuclear deterrent was centered around the Force de frappe, a nuclear triad consisting of Dassault Mirage IV bombers carrying such nuclear weapons as the AN-22 gravity bomb and the ASMP stand-off attack missile, Pluton and Hades ballistic missiles, and the Redoutable class submarine armed with strategic nuclear missiles. 

The People's Republic of China became the fifth nuclear power on October 16, 1964 when it detonated a 25 kiloton uranium-235 bomb in a test codenamed 596 at Lop Nur. In the late 1950s, China began developing nuclear weapons with substantial Soviet assistance in exchange for uranium ore. However, the Sino-Soviet ideological split in the late 1950s developed problems between China and the Soviet Union. This caused the Soviets to cease helping China develop nuclear weapons. However, China continued developing nuclear weapons without Soviet support and made remarkable progress in the 1960s. Due to Soviet/Chinese tensions, the Chinese might have used nuclear weapons against either the United States or the Soviet Union in the event of a nuclear war between the United States and the Soviet Union. During the Cold War, the Chinese nuclear deterrent consisted of gravity bombs carried aboard H-6 bomber aircraft, missile systems such as the DF-2, DF-3, and DF-4, and in the later stages of the Cold War, the Type 092 ballistic missile submarine. On June 14, 1967, China detonated its first hydrogen bomb.

Cuban Missile Crisis

More than 100 US-built missiles having the capability to strike Moscow with nuclear warheads were deployed in Italy and Turkey in 1961

 

On January 1, 1959, the Cuban government fell to communist revolutionaries, propelling Fidel Castro into power. The Soviet Union supported and praised Castro and his resistance, and the new government was recognized by the Soviet government on January 10. When the United States began boycotting Cuban sugar, the Soviet Union began purchasing large quantities to support the Cuban economy in return for fuel and eventually placing nuclear ballistic missiles on Cuban soil. These missiles would be capable of reaching the United States very quickly. On October 14, 1962, an American spy plane discovered these nuclear missile sites under construction in Cuba.

President Kennedy immediately called a series of meetings for a small group of senior officials to debate the crisis. The group was split between a militaristic solution and a diplomatic one. President Kennedy ordered a naval blockade around Cuba and all military forces to DEFCON 3. As tensions increased, Kennedy eventually ordered U.S. military forces to DEFCON 2. This was the closest the world has been to a nuclear war. While the U.S. military had been ordered to DEFCON 2, reaching a nuclear war was still a ways off. The theory of mutually assured destruction seems to put the entry into nuclear war an unlikely possibility. While the public perceived the Cuban Missile Crisis as a time of near mass destruction, the leaders of the United States and the Soviet Union were working behind the sight of the public eye in order to come to a peaceful conclusion. Premier Khrushchev writes to President Kennedy in a telegram on October 26, 1962 saying that, "Consequently, if there is no intention to tighten that knot and thereby to doom the world to the catastrophe of thermonuclear war, then let us not only relax the forces pulling on the ends of the rope, let us take measures to untie that knot." It is apparently clear that both men wanted to avoid nuclear war due to mutually assured destruction which leads to the question of just how close the world was from experiencing a nuclear war. 

Eventually, on October 28, through much discussion between U.S and Soviet officials, Khrushchev announced that the Soviet Union would withdraw all missiles from Cuba. Shortly after, the U.S. withdrew all their nuclear missiles from Turkey in secret, which had threatened the Soviets. The U.S.'s withdrawal of their Jupiter Missiles from Turkey was kept private for decades after, causing the negotiations between the two nations to appear to the world as a major U.S. victory. This ultimately led to the downfall of Premier Khrushchev.

Détente

U.S. President Richard Nixon with Soviet General Secretary Leonid Brezhnev, 1973

 

By the 1970s, with the cold war entering its 30th year with no direct conflict between the superpowers, the United States and the Soviet Union entered a period of reduced conflict, in which the two powers engaged in trade and exchanges with each other. This period was known as détente. This period included negotiation of a number of arms control agreements, building with the Nuclear Test Ban Treaty in the 1950s, but with significant new treaties negotiated in the 1970s. These treaties were only partially successful. Although both states continued to hold massive numbers of nuclear weapons and research more effective technology, the growth in number of warheads was first limited, and later, with the START I, reversed.

Treaties

In 1958, both the U.S. and Soviet Union agreed to informally suspend nuclear testing. However, this agreement was ended when the Soviets resumed testing in 1961, followed by a series of nuclear tests conducted by the U.S. These events led to much political fallout, as well as the Cuban Missile Crisis in 1962. Something had to be done to ease the great tensions between these two countries, so on October 10, 1963, the Limited Test Ban Treaty (LTBT) was signed. This was an agreement between the U.S., the Soviet Union, and the U.K., which significantly restricted nuclear testing. All atmospheric, underwater, and outer space nuclear testing were agreed to be halted, but testing was still allowed underground. An additional 113 countries have signed this treaty since 1963.

SALT I and SALT II limited the size of the states' arsenals. Bans on nuclear testing, anti-ballistic missile systems, and weapons in space all attempted to limit the expansion of the arms race through the Partial Test Ban Treaty. 

In November, 1969, Strategic Arms Limitation Talks (SALT) begun. This was primarily due to the economic impact that nuclear testing and production had on both U.S. and Soviet economies. The SALT I Treaty, which was signed in May, 1972, produced an agreement on two significant documents. These were the Anti-Ballistic Missile Treaty (ABM Treaty) and the Interim Agreement on the Limitation of Strategic Offensive Arms. The ABM treaty limited each country to two ABM sites, while the Interim Agreement froze each country's number of intercontinental ballistic missiles (ICBMs) and submarine-launched ballistic missiles (SLBMs) at current levels for five years. This treaty significantly reduced nuclear-related costs as well as the risk of nuclear war. However, SALT I failed to address how many nuclear warheads could be placed on one missile. A new technology, known as multiple-independently targetable re-entry vehicle (MIRV), allowed single missiles to hold and launch multiple nuclear missiles at targets while in mid-air. Over the next 10 years, the Soviet Union and U.S added 12,000 nuclear warheads to their already built arsenals.

Throughout the 1970s, both the Soviet Union and United States replaced old missiles and warheads with newer, more powerful and effective ones. This continued to worsen Soviet-U.S relations. On June 18, 1979, the SALT II treaty was signed in Vienna. This treaty limited both sides' nuclear arsenals and technology. However, in light of the Soviet Union's invasion of Afghanistan in December 1979, the United States Senate never ratified the SALT II treaty. This ended the treaty negotiations as well as the era of détente. The United States once again significantly increased military and nuclear spending, while the Soviets were unable to respond and continued to pursue détente. 

In 1991, the START (Strategic Arms Reduction Treaty) was negotiated between the U. S. and the Soviet Union, to reduce the number and limit the capabilities of limitation of strategic offensive arms. This was eventually succeeded by the START II, START III, and New START treaties.

Reagan and the Strategic Defense Initiative

Protest in Bonn, West Germany against the nuclear arms race between the U.S./NATO and the Soviet Union, 1981

 

Despite détente, both sides continued to develop and introduce more accurate weapons and weapons with more warheads ("MIRVs"). The presidency of Ronald Reagan proposed a missile defense programmed tagged the Strategic Defense Initiative, a space based anti-ballistic missile system derided as "Star Wars" by its critics; simultaneously, missile defense was also being researched in the Soviet Union. However, the SDI would require technology that had not yet been developed, or even researched. This system proposed both space- and earth-based laser battle stations. It would also need sensors on the ground, in the air, and in space with radar, optical, and infrared technology to detect incoming missiles. Simultaneously, however, Reagan initiated negotiations with Mikhail Gorbachev ultimately resulting in the Strategic Arms Reduction Treaty on reducing nuclear stockpiles.

Due to high costs and complex technology for its time, the scope of the SDI project was reduced from defense against a massive attack to a system for defending against limited attacks, transitioning into the Ballistic Missile Defense Organization.

The end of the Cold War

Soviet General Secretary Gorbachev and U.S. President Reagan signing the INF Treaty, 1987

 

During the mid-1980s, the U.S-Soviet relations significantly improved, Mikhail Gorbachev assumed control of the Soviet Union after the deaths of several former Soviet leaders, and announced a new era of perestroika and glasnost, meaning restructuring and openness respectively. Gorbachev proposed a 50% reduction of nuclear weapons for both the U.S and Soviet Union at the meeting in Reykjavik, Iceland in October 1986. However, the proposal was refused due to disagreements over Reagan's SDI. Instead, the Intermediate Nuclear Forces (INF) Treaty was signed on December 8, 1987 in Washington, which eliminated an entire class of nuclear weapons.

Due to the dramatic economic and social changes occurring within the Soviet Union, many of its constituent republics began to declare their independence. With the wave of revolutions sweeping across Eastern-Europe, the Soviet Union was unable to impose its will on its satellite states and so its sphere of influence slowly diminished. By December 16, 1991, all of the republics had declared independence from the Union. The Soviet leader, Mikhail Gorbachev resigned as the country's President on December 25 and the Soviet Union was declared non-existent the following day.

Post–Cold War

Dmitry Medvedev with Barack Obama after signing the New START treaty in Prague, 2010

 

With the end of the Cold War, the United States and Russia cut down on nuclear weapons spending. Fewer new systems were developed and both arsenals were reduced; although both countries maintain significant stocks of nuclear missiles. In the United States, stockpile stewardship programs have taken over the role of maintaining the aging arsenal.

After the Cold War ended, large inventories of nuclear weapons and facilities remained. Some are being recycled, dismantled, or recovered as valuable substances. As a result, a large amount of resources and money which was once spent on developing nuclear weapons in Soviet Union was then spent on repairing the environmental damage produced by the nuclear arms race, and almost all former production sites are now major cleanup sites. In the United States, the plutonium production facility at Hanford, Washington and the plutonium pit fabrication facility at Rocky Flats, Colorado are among the most polluted sites.

Military policies and strategies have been modified to reflect the increasing intervals without major confrontation. In 1995, United States policy and strategy regarding nuclear proliferation was outlined in the document "Essentials of Post–Cold War Deterrence", produced by the Policy Subcommittee of the Strategic Advisory Group (SAG) of the United States Strategic Command.

On April 8, 2010, former U.S. President Barack Obama and Russian President Dmitry Medvedev signed the New START Treaty, which called for a fifty percent reduction of strategic nuclear missile launchers and a curtailment of deployed nuclear warheads.^[38] The U.S. Senate ratified the treaty in December 2010 by a three-quarter majority.

Large stockpile with global range (dark blue), smaller stockpile with global range (medium blue), small stockpile with regional range (light blue).

 

On 13 December 2001, George W. Bush gave Russia notice of the United States' withdrawal from the Anti-Ballistic Missile Treaty. This led to the eventual creation of the American Missile Defense Agency. Russian President Vladimir Putin responded to the withdrawal by ordering a build-up of Russia's nuclear capabilities, designed to counterbalance U.S. capabilities.

On December 22, 2016, U.S. President Donald Trump proclaimed in a tweet that "the United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes," effectively challenging the world to re-engage in a race for nuclear dominance. The next day, Trump reiterated his position to Morning Joe host Mika Brzezinski of MSNBC, stating: "Let it be an arms race. We will outmatch them at every pass and outlast them all."

In October 2018, the former Soviet leader Mikhail Gorbachev commented that U.S. withdrawal from the INF nuclear treaty is "not the work of a great mind" and that "a new arms race has been announced".

In early 2019, more than 90% of world's 13,865 nuclear weapons were owned by Russia and the United States.

India and Pakistan

In South Asia, India and Pakistan have also engaged in a technological nuclear arms race since the 1970s. The nuclear competition started in 1974 with India detonating the device, codename Smiling Buddha, at the Pokhran region of the Rajasthan state. The Indian government termed this test as a "peaceful nuclear explosion", but according to independent sources, it was actually part of an accelerated covert nuclear program of India.

This test generated great concern and doubts in Pakistan, with fear it would be at the mercy of its long–time arch rival. Pakistan had its own covert atomic bomb projects in 1972 which extended over many years since the first Indian weapon was detonated. After the 1974 test, Pakistan's atomic bomb program picked up a great speed and accelerated its atomic project to successfully build its own atomic weapons program. In the last few decades of the 20th century, India and Pakistan began to develop nuclear-capable rockets and nuclear military technologies. Finally, in 1998 India, under Atal Bihari Vajpayee government, test detonated 5 more nuclear weapons. Domestic pressure within Pakistan began to build steam and Prime Minister Nawaz Sharif ordered the test, detonated 6 nuclear war weapons (Chagai-I and Chagai-II) in a tit-for-tat fashion and to act as a deterrent.

Defense against nuclear attacks

From the beginning of the Cold War, The United States, Russia, and other nations have all attempted to develop Anti-ballistic missiles. The United States developed the LIM-49 Nike Zeus in the 1950s in order to destroy incoming ICBMs.

Russia has, too, developed ABM missiles in the form of the A-35 anti-ballistic missile system and the later A-135 anti-ballistic missile system. Chinese state media has also announced to have tested anti-ballistic missiles, though specific information is not public.

India has successfully developed its Ballistic Missile Shield in the programme Indian Ballistic Missile Defence Programme with the test fire of Prithvi Air Defense (PAD) and it has also developed a cruise missile defense Akash Air Defense (AAD) to intercept low flying missiles making India one of the five countries with Missile Shield.