geopolitics of nuclear weapons

What determines the global power balance?

January 26, 2025

  • We explore nuclear doctrines, governance, global warhead stockpiles and conflict scenarios.

 

A nuclear weapon is an explosive device designed to release energy from splitting or merging atoms, significantly more powerful than conventional bombs or rockets.

 

The atomic bomb, which relies on nuclear fission, has limited explosive power.

 

The thermonuclear weapon, which uses a combination of nuclear fission and fusion, is even more powerful.

 

Kiloton (kt) and megaton (mt) are the units that measure a nuclear weapon’s explosive power, in comparison to that of TNT, a common chemical explosive.

 

1kt is equivalent to 1,000 tons of TNT, while 1mt is equivalent to 1,000,000 tons.

 

Little Boy, the atomic bomb dropped by the US on Hiroshima, Japan during the Second World War, had an explosive power of about 15 kilotons and killed 66,000 people.

 

Tsar Bomba, the most powerful thermonuclear weapon ever developed, was tested by the USSR in 1961 and had an explosive power of about 50 megatons.

  • Currently, about 1,000 mt of nuclear warheads globally are ready to be delivered in a first strike.

 

As of 2024, eight countries officially possess nuclear weapons, and Israel is widely believed to have them.

 

There are three primary nuclear weapons delivery systems:

  • Bombs are dropped from an aircraft and rely on gravity to fall on their target.

  • Ballistic missiles are rockets that can be launched from land, ship or submarine, and generally fly in an inverted U-shape before hitting the target. The warhead can have additional guidance systems or split into many.

  • Cruise missiles are effectively unmanned aircraft that use jet engines to deliver a warhead to a target. They can be launched from land, sea or aircraft.

 

Hypersonic missiles travel much faster than the speed of sound and turn unpredictably, making them difficult to shoot down.

 

The nuclear triad is the capability to launch nuclear weapons from sea, land and air, currently possessed by China, India, Russia, the US and likely Israel.

 

The nuclear triad strengthens deterrence by enabling a country to launch a counterstrike.

 

Both atomic bombs and thermonuclear weapons can have different uses:

  • Tactical nuclear weapons are used against limited military objectives – their power often ranges between 1 and 50 kt. Those would be delivered with short-range ballistic missiles that cover a distance under 500 kilometres.

  • Strategic nuclear weapons are meant for large-scale destruction and deterrence – their explosive power can reach several megatons. Those would be delivered with intercontinental ballistic missiles, submarine-launched ballistic missiles, cruise missiles or with long-range bomber aircraft.

Global nuclear governance

 

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) entered force in 1970.

  • It established a framework to prevent the spread of nuclear weapons based on three pillars: (1) non-proliferation, (2) disarmament, and (3) peaceful use.

 

Proliferation refers to a quick increase in number, but in the context of nuclear weapons means any spread of availability of nuclear weapons or material, including to non-government actors.

 

The NPT recognised five nuclear-weapon states – the US, Russia, China, France and the UK – but did not recognise India, Pakistan, North Korea or Israel as such.

 

As of 2024, 191 countries have signed the treaty. India, Pakistan, and Israel have never signed it, while North Korea withdrew in 2023.

 

The NPT has been followed by other treaties, such as the 2010 New START, which limits Russian and US strategic nuclear capabilities.

 

The United Nations recognises five Nuclear-Weapons-Free-Zones:

  • Africa

  • Central Asia

  • Latin America and the Caribbean

  • South Pacific

  • Southeast Asia

The Iran nuclear deal was signed in 2015 to restrict Iran's nuclear program in exchange for the relief of sanctions imposed by the US, European Union and the United Nations.

 

The deal is still formally active but lost its effectiveness after the US withdrawal under President Trump in 2018.

 

The International Atomic Energy Agency, an intergovernmental organisation that promotes the secure use of nuclear energy and non-proliferation, had a monitoring role in the Iran nuclear deal.

 

 

The nuclear doctrine is a nation's official policy regarding the development, deployment and potential use of nuclear weapons.

  • Deterrence is central to every country's nuclear doctrine. It refers to the prevention of an attack due to the country’s ability to launch a destructive counter-strike. 

 

First use nuclear policy allows a pre-emptive nuclear strike if the country decides it is threatened.

 

No first use nuclear policy allows the use of nuclear weapons only as a response to being attacked with weapons of mass destruction.

  • Strategic ambiguity refers to not disclosing the nuclear doctrine to use the uncertainty to your advantage.

 

A counterforce doctrine targets military infrastructure, while a countervalue doctrine targets civilian and economic infrastructure aimed at causing maximum psychological and material damage.

 

United States

 

Nuclear doctrine: First use

 

  • The US considers Russia its most capable nuclear rival, and China as an emerging nuclear threat.

  • The US nuclear policy's three primary objectives are (1) to deter aggression, (2) to reassure its allies, and (3) if deterrence fails, to deploy nuclear weapons to protect its vital interests.

  • The US supports non-proliferation and is open to discussing a new nuclear weapons control treaty with Russia.

 

Documents: Nuclear Posture Review (2022), Nuclear Weapons Employment Strategy (2024)

 

Russia

 

Nuclear doctrine: First use

  • Russia can use nuclear weapons in response to (1) a nuclear attack or (2) a conventional attack that threatens its sovereignty or territorial integrity, even if the aggressor is a non-nuclear state but is supported by a nuclear state.

  • The doctrine was adjusted in 2024 to reduce restrictions on first use of nuclear weapons.

  • Russia considers any attack against Belarus as an attack against itself.

 

Documents: Fundamentals of State Policy of the Russian Federation in the Field of Nuclear Deterrence (2024)


China

 

Nuclear doctrine: No first use

  • China maintains a minimal nuclear arsenal for deterrence, self-defence and a potential retaliatory strike.

  • China is committed to global nuclear disarmament.

 

Documents: China's National Defense in the New Era (2019), No-First-Use of Nuclear Weapons Initiative (2024)

 

France

 

Nuclear doctrine: Deliberate ambiguity

  • France's nuclear arsenal protects its vital interests, which include the European Union's security.

  • France maintains a minimal nuclear arsenal for deterrence.

 

Documents: French Nuclear Doctrine Document (2024)

 

United Kingdom

 

Nuclear doctrine: Deliberate ambiguity

  • The UK always has an active nuclear-armed submarine on patrol.

  • The UK is committed to a strategic nuclear partnership with France and the US but affirms its strategic independence from them.

  • The UK supports non-proliferation and global nuclear disarmament.

 

Documents: Integrated Review (2021), Defence Nuclear Command Paper (2023)

 

India

 

Nuclear doctrine: No first use, but allowing nuclear weapons to retaliate against chemical or biological attacks.

  • India maintains a minimal nuclear arsenal for deterrence.

  • India is not a signatory of the NPT but advocates for global disarmament.

 

Documents: Cabinet Committee on Security Document (2003)

 

Pakistan

 

Nuclear doctrine: Deliberate ambiguity

  • Pakistan adopts full-spectrum deterrence, which includes threatening the use of nuclear capabilities even in response to low-scale conventional attacks.

  • Pakistan shifted from a countervalue to a combination of counterforce and countervalue doctrines.

 

No official nuclear policy documents.

 

Israel

 

Nuclear doctrine: Deliberate ambiguity

  • Israel allows first use against adversaries that are close to obtaining nuclear weapons – the Begin doctrine.

  • Israel can counter any country posing an existential threat with a mass nuclear strike – the Samson option.

 

No official nuclear policy documents.

 

North Korea

 

Nuclear doctrine: First use

  • North Korea's President Kim Jong Un is the ultimate decision-maker for the use of nuclear weapons.

  • North Korea can use its nuclear weapons both for deterrence or pre-emptive strikes.

 

Documents: Law on the DPRK's Nuclear Forces Policy (2022)

Nuclear war scenarios

 

While hypothetical, these provide insight into what eventualities countries have to be prepared for.

 

India and Pakistan

 

Possible nuclear war triggers:

  • Tensions over Kashmir, a region whose control is contested by India and Pakistan.

  • Pakistan's alleged or proven support for terrorist groups attacking India.

  • Misunderstanding the opponents' military actions or a failure in the early warning system used for detecting potential attacks.

 

A nuclear missile from India to Pakistan, or the other way, would take only four minutes to reach its target.

 

India would deploy its nuclear arsenal, including BrahMos, an advanced cruise missile jointly developed with Russia, against Pakistan's military infrastructure.

 

Pakistan would also deploy its nuclear arsenal, which is less advanced and lacks submarine capability. 

 

According to estimates from 2007, a nuclear war between India and Pakistan would cause 27 million immediate deaths. Considering nuclear weapons modernisation and population growth, casualties would be even higher today.

 

A regional nuclear war between India and Pakistan would also impact the earth's climate and global agriculture. This would cause more than 2 billion people to die from starvation in the long term.

 

US and Russia

 

In a full-scale nuclear war between Russia and the US, approximately 4,000 nuclear warheads, with an average power of 100 kt, could be deployed.

  • Such a war could kill hundreds of millions and severely disrupt the earth's climate.

 

A scenario by Princeton University describes a conventional war between NATO and Russia escalating into a nuclear conflict after Russia launches a strike on Poland to prevent the advancement of NATO troops.

 

NATO then strikes the launch site in Kaliningrad and Russia retaliates with a mass nuclear attack on NATO’s capabilities, before the US launches a counterforce strike in response. 

 

An important factor in assessing the power balance is air-defence capability.

 

US and NATO systems:

 

•    GMD – capability to intercept long-range ballistic missiles with a direct hit, before they enter their final stage and potentially split.
•    Aegis system – capability to intercept short- to medium-range missiles from land or sea.
•    THAAD – capability to intercept warheads of short- to long-range ballistic missiles during the final stage.
•    Patriot system – capability to intercept short- to medium-range ballistic missiles, cruise missiles and aircraft at a limited range, potentially effective against some hypersonic missiles. 

 

Russian systems:

 

•    A-135/235 – capability to intercept long-range ballistic missiles in Western Russia.
•    S-300/400/500 – capability to intercept aircraft or ballistic and cruise missiles at a limited range.

US and Russia are actively developing new capabilities for intercepting advanced and hypersonic missiles, while also improving their own capabilities to penetrate air-defences with manoeuvring, guided and splitting warheads. 

Author Elia Preto Martini

Editor Anton Kutuzov

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