Nuclear deterrence is a strategic doctrine holding that the possession of nuclear weapons by a state - or an alliance - prevents adversaries from launching nuclear or large-scale conventional attacks by threatening an unacceptable retaliatory cost. The concept rests on the premise that rational actors will not initiate a conflict they cannot win without suffering destruction proportionate to or greater than any potential gain. Since the first use of nuclear weapons in August 1945, deterrence has shaped the structure of great-power competition, alliance commitments, arms control negotiations, and military doctrine worldwide.

Nuclear deterrence encompasses several related but distinct concepts. Minimum deterrence holds that a small, survivable arsenal sufficient to guarantee retaliation is adequate. Extended deterrence describes a nuclear-armed state's commitment to defend non-nuclear allies - most prominently the United States' “nuclear umbrella” over NATO members and treaty partners in East Asia. Mutual assured destruction (MAD) describes a condition in which two adversaries each possess sufficient second-strike capability that a first strike by either side would result in the annihilation of both. Counterforce targeting aims weapons at an adversary's military assets; countervalue targeting aims at population and industrial centers. The balance between these postures has been a persistent source of strategic and ethical debate.

The doctrine emerged from the Manhattan Project and the bombings of Hiroshima and Nagasaki in August 1945. The Soviet Union's first nuclear test in 1949 inaugurated the bipolar nuclear competition that defined Cold War strategy. Key developments included the hydrogen bomb, intercontinental ballistic missiles, submarine-launched ballistic missiles, multiple independently targetable reentry vehicles (MIRVs), and successive arms control treaties from SALT I (1972) through New START (2010). For a full account, see Nuclear Deterrence - History.

As of the mid-2020s, nine states are confirmed or widely assessed to possess nuclear weapons: the United States, Russia, the United Kingdom, France, China, India, Pakistan, Israel (undeclared), and North Korea. The combined global stockpile numbers in the thousands of warheads, with the United States and Russia each holding the large majority. China is assessed to be expanding its arsenal significantly. The 1968 Nuclear Non-Proliferation Treaty (NPT) remains the central multilateral framework, though its long-term durability is disputed given non-signatories, treaty withdrawals, and the perceived gap between disarmament obligations and the modernization programs of established nuclear states.

Extended deterrence commitments have come under renewed scrutiny following Russia's invasion of Ukraine in 2022 and ongoing tensions over Taiwan. NATO's nuclear posture - coordinated through the Nuclear Planning Group and articulated in its Strategic Concept - is summarized at NATO Security Consensus. The scope and stability of deterrence in a multipolar environment is actively contested; see Nuclear Deterrence - Debate.

A NATO Security Consensus exists among alliance members supporting nuclear deterrence as a component of collective defense. The breadth and content of broader international scholarly and policy consensus on deterrence stability, sufficiency, and the conditions under which deterrence may fail is contested; see Nuclear Deterrence - Strategic Consensus for that landscape.

• Classical deterrence stability - The view that mutual second-strike capability produces stable deterrence and that rational actors will avoid nuclear use as long as assured destruction remains credible. Viewpoint page
• Minimum deterrence / sufficiency - The view that large arsenals are strategically unnecessary and politically counterproductive, and that small survivable forces are both adequate and less escalatory. Viewpoint page
• Nuclear abolitionism - The view that deterrence is morally impermissible and strategically fragile, and that the only acceptable endpoint is verified universal disarmament, as represented by the Treaty on the Prohibition of Nuclear Weapons (TPNW, 2021). Viewpoint page
• Counterforce primacy - The view that targeting adversary weapons and command infrastructure rather than populations is both more ethical and more strategically effective at limiting damage if deterrence fails. Viewpoint page
• Extended deterrence skepticism - The view that security guarantees to non-nuclear allies lack credibility because a nuclear-armed state would not risk its own destruction to honor alliance commitments, creating incentives for allies to proliferate. Viewpoint page
• Proliferation stability / instability - Disputed positions on whether the spread of nuclear weapons to additional states increases or decreases the probability of nuclear use. Debate page

• Nuclear Deterrence - History
• Nuclear Deterrence - Debate
• Nuclear Deterrence - Strategic Consensus
• NATO Security Consensus
• Arms Control
• Nuclear Nonproliferation
• Mutual Assured Destruction
• Extended Deterrence

1. Brodie, Bernard, ed. The Absolute Weapon: Atomic Power and World Order. Harcourt, Brace, 1946. Foundational articulation of deterrence theory.
2. Schelling, Thomas C. The Strategy of Conflict. Harvard University Press, 1960.
3. Schelling, Thomas C. Arms and Influence. Yale University Press, 1966.
4. Waltz, Kenneth N. The Spread of Nuclear Weapons: More May Be Better. Adelphi Papers No. 171. IISS, 1981.
5. Sagan, Scott D., and Kenneth N. Waltz. The Spread of Nuclear Weapons: An Enduring Debate. 3rd ed. W. W. Norton, 2012.
6. Treaty on the Non-Proliferation of Nuclear Weapons, opened for signature 1 July 1968, entered into force 5 March 1970.
7. Treaty on the Prohibition of Nuclear Weapons, adopted 7 July 2017, entered into force 22 January 2021.
8. New START Treaty (Treaty Between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms), signed 8 April 2010.
9. NATO. “NATO's Nuclear Deterrence Policy and Forces.” NATO Fact Sheet. Updated 2023. https://www.nato.int/cps/en/natohq/topics_50068.htm
10. Kristensen, Hans M., and Matt Korda. “Status of World Nuclear Forces.” Federation of American Scientists, 2024. https://fas.org/initiative/status-world-nuclear-forces/