Nuclear Weapons and Foreign Policy

 Nuclear Weapons and Foreign Policy

Exploring the linkages

“What happens to the foreign policies of states when they acquire nuclear weapons?” This question has grown in importance as new nuclear powers have emerged and some other states have moved closer to joining the nuclear club. Indeed, determining the costs the world should be prepared to pay to prevent nuclear proliferation hinges on assessing how nuclear weapons affect the behaviour of the states that acquire them and how dangerous those effects are. If states expand their interests in world politics or act more aggressively in the aftermath of nuclear acquisition, preventing nuclear proliferation should be a higher priority. Crafting deterrence strategies for new nuclear states also requires understanding of the foreign policy effects that nuclear weapons are likely to have in a given case.

There are basically three assumptions that help us understand the role of nuclear capability in the formulation of the foreign policy of a country:

1. First, nuclear weapons affect a state’s foreign policy because they provide capabilities that the state previously lacked. This assumption suggests that nuclear weapons should begin to affect a state’s foreign policy at the point at which they can be used in the way the state intends to use them. For example, if a state employs a catalytic posture that aims to compel outside intervention by threatening a nuclear test, only the ability to conduct a nuclear test is required for nuclear weapons to affect calculations about foreign policy. If, however, a state anticipates using nuclear weapons to hit strategic targets in an adversary’s homeland, then nuclear weapons should affect a state’s foreign policy at the point at which the state can deliver nuclear weapons to those targets. For example, Britain envisioned delivering nuclear weapons to the cities of the Soviet Union, so nuclear weapons should have begun to affect British foreign policy once Britain possessed the capacity to deliver nuclear weapons to the Soviet Union.

2. Second, the threat of using nuclear weapons is credible under at least some circumstances. The literature on nuclear deterrence also relies on this assumption, because the deterrent power of nuclear weapons depends on the possibility of nuclear use.

3. Third, states seek to use their nuclear weapons to protect and pursue their interests. In other words, states are strategic actors that do not spend time and resources acquiring nuclear weapons only to ignore the benefits that they offer.

With these assumptions as a starting point, we can identify six foreign policy behaviours that nuclear weapons can facilitate.

1. Aggression

First, nuclear weapons may facilitate aggression — Aggression is defined as the more belligerent pursuit of goals in preexisting disputes or in pursuit of previously articulated interests. Nuclear weapons may reduce the price of this behaviour because they add a layer of military capability that can be called upon, or that might be used inadvertently by leaders enveloped by the fog of war. As a result, nuclear weapons raise the risk of escalation for the state’s opponents in responding to aggression, which must now reckon with both the conventional forces the state previously possessed and their nuclear capabilities. Hence, the threat of nuclear escalation can act as a shield behind which aggression can be undertaken. Nuclear weapons can, therefore, make more attractive opportunities to escalate conflicts or revise the status quo.

Pakistan provides an example of a state in this position. The country has used its nuclear weapons to thwart the Indian aggression. In the face of a proximate and conventionally superior Indian threat, and possessing revisionist preferences, Pakistan has used nuclear weapons as a shield behind which it has pursued more aggressively its foreign policy goals.

2. Expansion

Second, nuclear weapons can facilitate expansion. Expansion is defined as the widening of a state’s goals in international politics, leading to new interests, rather than more aggressive pursuit of existing interests. Expansion is primarily composed of two dyadic foreign policy behaviours: the formation of new dyadic alliance relationships and the initiation of new dyadic adversarial relationships. Nuclear weapons may reduce the cost of expansion because they allow states to free up conventional military and political resources that were previously dedicated to military tasks the state can now accomplish with nuclear weapons or by relying on nuclear deterrence. These freed-up forces can then be redeployed in pursuit of new interests at lower risk than would have been possible without nuclear weapons.

States facing a favourable security environment and rising in power are likely to be most interested in using nuclear weapons to facilitate expansion as such states do not need to deal with immediate threats, and rising powers frequently seek to expand their influence and reach in international politics as their power position improves. Nuclear weapons offer them a tool that facilitates such behaviour. The United States provides an example of a state in this position that pursued expansion in the aftermath of acquiring nuclear weapons. Nuclear weapons played a key role in the US Cold War strategy to contain the Soviet Union, facilitated a semi-permanent US military presence in Europe, and allowed the United States to extend nuclear deterrence to a range of new allies. Nuclear weapons thus permitted the United States to pursue a vastly more expansive grand strategy than had ever previously been considered in its history.

3. Independence

Third, nuclear weapons may reduce the costs associated with a state acting independently of allies or other states that help provide for a state’s security. Independence is the taking of actions that an ally either opposes or does not support the state taking. Nuclear weapons affect the cost of independence by providing an internal source of military power that the state previously lacked. Hence these weapons can act as a partial substitute for external sources of military power (alliances).

Nuclear weapons can thus allow states to overcome the dissatisfaction stemming from compromises of foreign policy autonomy necessary to retain a patron’s support. Because states with nuclear weapons have less need for an ally’s protection, they should be less inclined to compromise their own goals in exchange for protection.

France provides an example of a state using nuclear weapons to facilitate independence. Upon acquiring a deliverable capability in 1964, France became more comfortable acting independently of the United States and took a series of actions despite American opposition, including criticizing the Bretton Woods monetary system, pursuing détente with the Soviet Union, recognizing China, and withdrawing from NATO’s command structure. Similarly, observers have argued that North Korea’s nuclear weapons allow Pyongyang to defy its Chinese patron. Jonathan Pollack argues that “the desire to be answerable to no external power” drove North Korea’s nuclear programme, and that its nuclear weapons inhibit China’s ability to control North Korea or sever Beijing’s ties with Pyongyang.

4. Bolstering

Fourth, nuclear weapons may reduce the costs associated with bolstering which is defined as the taking of actions to improve the credibility or strength of an alliance or ally. Thus, whereas independence involves using nuclear weapons as a substitute for an alliance, bolstering involves using nuclear weapons to augment an alliance. Nuclear weapons can reduce the costs associated with bolstering in several ways. First, nuclear weapons provide a state with resources that it can offer to an ally, such as by transferring sensitive nuclear technologies. Second, nuclear weapons may offer the ability to defend an alliance partner at lower cost than with conventional forces. Third, having nuclear weapons may help a state deter attacks on its ally directly, thus making the alliance less costly to maintain and reducing the costs of making a stronger alliance commitment.

A range of states are likely to find it attractive to use nuclear weapons to bolster allies. States facing severe security threats may prefer to focus on using their nuclear weapons to provide for their own security than to enhance the security of others; but among states not facing such binding constraints, many may find bolstering allies to be attractive.

For example, China provided Pakistan with highly-enriched uranium and a nuclear weapon design to bolster Pakistan against their common adversary, India. Indeed, the transfer of nuclear technologies is often undertaken to bolster allies against common enemies.

5. Steadfastness

Fifth, nuclear weapons may decrease the costs associated with steadfastness. Steadfastness is defined as a reduced inclination to back down in disputes or in response to coercion and an increased willingness to fight to defend the status quo. Nuclear weapons can reduce the cost of this behaviour by raising the risk of escalation for an opponent, making offensive threats against the nuclear state less credible, and reducing the danger for the nuclear state of refusing to back down. This logic—that nuclear weapons increase the level of escalation a state is willing to tolerate in a particular dispute—is the same as that underpinning aggression; but in the case of steadfastness, this leverage is used in defence of the status quo rather than in pursuit of revisionist goals.

Almost all states are likely to find it attractive to use nuclear weapons to stand more firmly in defence of the status quo, because few states like to be pushed around by others. Greater steadfastness, however, may not always be observed in the aftermath of acquisition, because states will appear more steadfast only in the event of challenges to their position: steadfastness will therefore be most observable in states that are regularly challenged. For example, Pakistani elites viewed the various India-Pakistan crises of the 1980s as validating the decision to acquire a nuclear capability, which “ensures defence against physical external aggression and coercion from adversaries, and deters infringement of national sovereignty.” Nuclear weapons allowed Pakistan to tolerate higher levels of escalation in disputes with India, and thus to stand more firmly in defence of what it perceived to be the status quo.

6. Compromise

Sixth, nuclear weapons may reduce the costs associated with compromise. Compromise is defined as the acceptance of less than what was previously demanded in pre-existing disputes. Nuclear weapons may reduce the cost of compromising in disputes because they provide a source of military capability (ergo security) that means that a state may face lower risks if it makes compromises. For example, if nuclear weapons make conventional aggression against the state less likely, then they also reduce the value of strategic depth and holding territory. The risks associated with making territorial compromises are, therefore, lower.

One possible case is that the Soviet withdrawals from Eastern Europe, Afghanistan, and Africa reflected the reduced benefits of controlling territory in the nuclear age. The role of nuclear weapons in these cases is contested, however, and even advocates of this view acknowledge that other factors influenced Soviet thinking. Nonetheless, scholars have frequently argued that states should use nuclear weapons to facilitate compromise.


A state may respond to nuclear acquisition by engaging in increasing quantities of more than one of the behaviours discussed above. Similarly, because of the dyadic nature of foreign policy, a state may engage in greater quantities of different behaviours toward different states.

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