The world’s nuclear-armed states each have declared, to varying degrees of specificity, when and under what circumstances they reserve the option to use their nuclear weapons. Most nuclear-armed states have also declared under what circumstances they rule out the use of nuclear weapons. These “positive” and “negative” nuclear declaratory policies are designed to deter adversaries from military actions and to assure non-nuclear weapon states and allies they will not be subject to a direct nuclear attack on their territory and should be dissuaded from pursuing nuclear weapons themselves.
Today, most nuclear-armed states, including the United States, reserve the option to use nuclear weapons first in a conflict. Only two nuclear-armed states (China and India) have declared no-first-use policies, by which they commit themselves to use nuclear weapons only in response to a nuclear attack.
All five of the nuclear-weapon states recognized in the nuclear Nonproliferation Treaty (NPT) (China, France, Russia, the United Kingdom, and the United States) have issued a set of “negative” nuclear security assurances, which were recognized by the UN Security Council in Resolution 984 (1995). These pledges, however, are nonbinding and some nuclear-weapon states reserve the right to use nuclear weapons against non-nuclear-weapon states under certain circumstances. The following is a more detailed summary of each country’s policies.
The 2018 Nuclear Posture Review report declared that there are four missions for the U.S. nuclear arsenal: deterrence of nuclear and non-nuclear attacks, assurance of allies and partners, achievement of U.S. objectives if deterrence fails, and capacity to hedge against an uncertain future.
The document reiterated that the United States does not maintain a nuclear “no first-use policy” on the grounds that U.S. response options must remain flexible to deter nuclear and non-nuclear attacks. “Non-nuclear capabilities,” according to the report, “can complement but not replace U.S. nuclear capabilities” for the purpose of deterrence. In the event that deterrence were to fail, the report also declared that Washington could use nuclear weapons to end a conflict on the “best achievable terms for the United States.”
The NPR dictates that the use of nuclear weapons will only be considered under “extreme circumstances” to defend the “vital interests” of the United States and its allies. It defines “extreme circumstances,” which the 2010 NPR did not, to include “significant non-nuclear strategic attacks” against “U.S., allied or partner civilian population or infrastructure, and attacks on U.S. or allied nuclear forces, their command and control, or warning and attack assessment capabilities.”
The United States issued assurances not to use nuclear weapons against non-nuclear-weapon-state NPT members in 1978, 1995 and 2010 except in the case of “an invasion or any other attack on the United States, its territories, its armed forces or other troops, its allies, or on a State toward which it has a security commitment, carried out or sustained by such a non-nuclear-weapon State in association or alliance with a nuclear- weapon State.” In 1997 the United States issued a classified presidential decision directive (PDD) reaffirming these pledges.
The 2018 NPR repeated existing U.S. negative security assurances by stating that Washington “will not use or threaten to use nuclear weapons against non-nuclear weapons states that are party to the NPT and in compliance with their nuclear non-proliferation obligations.” However, the report qualified that the United States reserves the right to amend its negative assurance if warranted by “the evolution and proliferation of non-nuclear strategic attack technologies.” At the February 2 press briefing following the report’s release, Undersecretary of Defense for Policy John Rood clarified that this may include cyber capabilities.
For a more details, see U.S. Negative Security Assurances at a Glance.
China issued negative security assurances at the United Nations in 1978 and 1995 and is the only NPT nuclear-weapon state that has declared a no-first-use policy, which it reiterated in February 2018.
At the 2018 Munich Security Conference, Fu Ying, chairperson of the foreign affairs committee of the National People’s Congress, said that “China is also committed to the principle of non-first-use of nuclear weapons, and no-use of nuclear weapons against any nuclear state [sic] at any circumstances and no-use of nuclear weapons against nuclear-free zones.”
In its April 1995 letter to UN members outlining its negative security assurances, China declared that it “undertakes not to be the first to use nuclear weapons at any time or under any circumstances.” China consistently reiterates this policy in its defense white papers. The most recent, edited in 2016, stated that “China will unconditionally not use or threaten to use nuclear weapons against non-nuclear-weapon states or in nuclear-weapon-free zones, and will never enter into a nuclear arms race with any other country.”
At the 2010 NPT Review Conference, China also called for the negotiation of an international legally binding instrument to prohibit first-use of nuclear weapons and use or threat of use of nuclear weapons against non-nuclear weapon states and nuclear-weapon free zones.
France maintains a policy of calculated ambiguity regarding first-use of nuclear weapons. A 2013 French government defense white paper states that “the use of nuclear weapons would only be conceivable in extreme circumstances of legitimate self-defence” and that “[b]eing strictly defensive, nuclear deterrence protects France from any state-led aggression against its vital interests, of whatever origin and in whatever form.”
France issued negative security assurances at the UN in 1987 and 1995. In its 1995 statement to the UN, France pledged not to use nuclear weapons against non-nuclear-weapon states that are party to the NPT “except in the case of invasion or any other attack on France, its territory, its armed forces or other troops, or against its allies or a State toward which it has a security commitment, carried out or sustained by such a State in alliance or association with a nuclear-weapon State.”
At the 2010 NPT Review Conference, France called for nuclear possessor states to “work resolutely to advance disarmament in all its aspects; in which the doctrines of nuclear powers will restrict the role of nuclear weapons solely to extreme circumstances of self-defence where their vital interests are under threat.”
According to the December 2014 Russian Military Doctrine Paper published by the Ministry of Defense, Russia reserves the option to use nuclear weapons in response to an attack involving any weapon of mass destruction, and in response to conventional attacks “when the very existence of the state is under threat.” This phrase suggests a willingness to use nuclear weapons against non-nuclear states in the event of an impending conventional military defeat.
In 1993, Russia moved away from Leonid Brezhnev’s 1982 no-first-use pledge when the Russian Defense Ministry under Boris Yeltsin adopted a new doctrine on nuclear weapons. The new policy ruled out the first use of nuclear weapons against non-nuclear-weapon states that are party to the NPT but said nothing about use against states possessing nuclear weapons. Since the 1993 shift, many Western analysts have come to believe that Russia pursues an “escalate to de-escalate” strategy—the notion that, in the event of a large-scale conventional conflict, the Kremlin would use or threaten to use low-yield nuclear weapons to coerce an adversary to cease attacks or withdraw. However, other analysts maintain that this is not the case.
Russia issued unilateral negative security assurances not to attack non-nuclear-weapon states in 1978 and 1995, but stated in 1995 that those pledges would not apply “in the case of an invasion or any other attack on the Russian Federation, its territory, its armed forces or other troops, its allies or on a State toward which it has a security commitment, carried out or sustained by such a non-nuclear-weapon State in association or alliance with a nuclear-weapon State.”
In the 2015 Strategic Defense and Security Review document, the United Kingdom said it will not use, or threaten to use, nuclear weapons against non-nuclear weapon states that are party to the NPT and in compliance with the treaty’s obligations. The United Kingdom appears to leave open the option to use nuclear weapons in response to WMD threats, such as chemical or biological attacks, if such threats emerge. Currently London acknowledged that there is “no direct threat” posed by WMDs to the United Kingdom in the 2015 document, but the government reserves the right to “review this assurance if the future threat, development or proliferation of these weapons make it necessary.”
The United Kingdom issued a unilateral negative nuclear security assurance in 1978 and again in 1995. In the 1995 pledge the United Kingdom said it will not use, or threaten to use, nuclear weapons against non-nuclear-weapon states party to the NPT. This assurance does not apply, however, to any state acting “in association or alliance with a nuclear-weapon state” that attacks the United Kingdom, its territories or allies, or any state in breach of its commitments under the NPT.
India has a no-first-use doctrine. As the government stated in a draft nuclear doctrine in August 1999, “India will not be the first to initiate a nuclear strike, but will respond with punitive retaliation should deterrence fail.” Although India has adopted a no-first-use policy, some Indian strategists have called the pledge’s validity into question. The credibility of this pledge was weakened in 2009 when Indian Army Chief Gen. Deepak Kapoor suggested that the government should review the pledge in light of the growing threat of Pakistan. In 2010, National Security Advisor Shivshankar Menon stated that India's nuclear doctrine was “no first use against non-nuclear weapons states.” MIT professor Vipin Narang has also observed that “the force requirements India needs in order to credibly threaten assured retaliation against China may allow it to pursue more aggressive strategies—such as escalation dominance or a ‘splendid first strike’—against Pakistan.”
During debate at the Conference on Disarmament in 2014, India’s representative reiterated the government’s no-first-use policy and the policy on nonuse against non-nuclear-weapon states and said that India was “prepared to convert these undertakings into multilateral legal arrangements.”
Given that Israel has not acknowledged possession of nuclear weapons, it has not made any statements regarding its willingness to use nuclear weapons against non-nuclear-weapon states. Israel generally abstains from voting on an annual UN General Assembly resolution that would establish international arrangements to assure non-nuclear-weapon states that the use or threat of use of nuclear weapons would not be used against them, including recently in resolution 72/25 in 2017.
Pakistan has only issued negative nuclear security guarantees to those states that are not armed with nuclear weapons. Pakistan’s position regarding when and whether it would use nuclear weapons in a conflict with another nuclear-armed state, namely India, is far more ambiguous. Pakistani officials have indicated that the circumstances surrounding its no-first-use policy must remain deliberately imprecise, as demarcating clear redlines could allow provocations by the Indian military just below any established threshold for use.
In a 2015 statement, Foreign Secretary Aizaz Ahmad Chaudhry said that Pakistan’s nuclear arsenal is one-dimensional, that is it for "stopping Indian aggression before it happens" “not for starting a war.” He also said in 2015 that Pakistan is capable of answering aggression from India due to Islamabad’s development of short-range tactical nuclear weapons. In July 2016, Pakistani Defense Minister Khawaja Asif suggested Islamabad would use nuclear weapons for defensive purposes in armed conflict with India.
Following its fourth nuclear test in January 2016, Pyongyang declared a policy of no-first-use under the condition that hostile forces do not encroach on its sovereignty. The Jan. 6, 2016 government statement said that North Korea, as a “responsible nuclear weapons state, will neither be the first to use nuclear weapons…as long as the hostile forces for aggression do not encroach upon its sovereignty.” North Korea has re-affirmed this stance at the May 2016 Worker's Party Congress in Pyongyang and in the 2018 New Year's Address. North Korea, however, routinely threatens to use nuclear weapons against perceived threats, including against the United States and South Korea, a non-nuclear-weapon state.