Geopolitics › Global issues & flashpoints
Nuclear weapons and proliferation
Since 1945; nine nuclear-armed states· Issue or flashpoint
FactTreaties, membership, measured data, events.
The spread and buildup of nuclear arms among nine states, and the weakening treaties meant to limit them.
See it on the Geopolitics map →The picture
Since the US bombed Hiroshima and Nagasaki in 1945, nine states now hold nuclear weapons: the US, Russia, Britain, France, China, India, Pakistan, North Korea and Israel (undeclared). SIPRI counted about 12,200 warheads in early 2025, roughly 90% Russian or American. The INF and New START treaties are gone, China is building fast, and Iran's enrichment helped trigger wars in 2025 and 2026. In October 2025 Trump ordered testing 'on an equal basis'; officials said that meant non-explosive tests.
Why it matters
Nuclear arms deter great-power war but make any clash between nuclear states, such as Russia–NATO, India–Pakistan or US–China, potentially catastrophic.
Key facts and numbers
SIPRI and Federation of American Scientists estimates built from official disclosures, budgets and satellite imagery; IAEA reports; treaty texts. Stockpiles are secret, so figures are estimates.
What to watch
Outlook: whether arms control revives or a three-way US–Russia–China race begins, and whether more states, such as Iran, Saudi Arabia or South Korea, seek weapons.
Inside this (2)
Connections (9)
▸France has the EU's only arsenal of Nuclear weapons and proliferationFact
The relationship
Under de Gaulle, France built its own deterrent so it would not depend on the US, testing first in the Algerian Sahara in 1960. Its roughly 290 warheads sit on submarines and aircraft. Since Brexit it is the EU's only nuclear power, and Macron has offered to discuss what its deterrent could mean for European allies.
Since when and why
First test on February 13, 1960 at Reggane, Algeria; Macron's offers in 2020 and March 2025; a July 2025 UK–France pact to coordinate their deterrents.
How we know
French defense white papers and presidential speeches, the 2025 Northwood Declaration with Britain, and warhead estimates from SIPRI and the Federation of American Scientists.
What to watch
Whether France would really risk its own cities to defend Berlin or Warsaw, and whether a European deterrent could ever replace the US nuclear umbrella.
▸Russia holds the largest arsenal of Nuclear weapons and proliferationFact
The relationship
Russia inherited the Soviet arsenal and holds about 5,500 warheads, the world's largest stockpile. Since 2022 Putin has used nuclear warnings to deter NATO involvement in Ukraine, lowered the threshold for use in a November 2024 doctrine, de-ratified the test-ban treaty in 2023 and announced tests of new nuclear-powered weapons in 2025.
Since when and why
Moscow; nuclear warnings from February 2022, the doctrine revised November 19, 2024, and Burevestnik cruise-missile and Poseidon torpedo tests announced in October 2025.
How we know
Russia's published nuclear doctrine, Kremlin statements, SIPRI and Federation of American Scientists estimates, and US intelligence assessments.
What to watch
How serious the warnings are, and whether Russia would ever use a tactical nuclear weapon in Ukraine; US officials reportedly saw the risk peak in late 2022.
▸Belarus hosts Russian Nuclear weapons and proliferationFact
The relationship
Belarus gave up its Soviet-era warheads in the 1990s. In 2023 Russia moved tactical nuclear weapons there, its first such deployment outside its borders since the Soviet breakup. Moscow keeps control of the warheads, which Belarusian aircraft and Iskander missiles can carry, and a December 2024 treaty extended Russia's nuclear guarantee to Belarus.
Since when and why
Announced by Putin in March 2023; Lukashenko said deliveries began in June 2023; the Union State security treaty was signed in Minsk in December 2024.
How we know
Putin's and Lukashenko's statements and satellite imagery of storage sites; outside analysts have not confirmed how many warheads are there.
What to watch
How many weapons are there and what Belarus's role in using them would be; NATO neighbors Poland and Lithuania see the move as a direct threat.
▸Iran's nuclear program is a proliferation flashpoint in Nuclear weapons and proliferationWidely agreed
The relationship
Iran's 60% enrichment left it, by US and IAEA estimates, only weeks from bomb-grade fuel for several weapons. That threatened to make it a tenth nuclear-armed state and spur others: Saudi Arabia says it would match an Iranian bomb. It is also the main test of whether the NPT can stop a determined state.
Since when and why
IAEA reports of 60% enrichment from 2021; crises peaking in the June 2025 and February 2026 strikes; the IAEA board's referral to the UN Security Council, September 2026.
How solid?
IAEA quantitative reports, including the 440.9 kg stockpile figure, US intelligence assessments, and Crown Prince Mohammed bin Salman's public statements in 2018 and 2023.
What to watch
Disputed: US intelligence long judged Iran was not actively building a bomb; whether the strikes delayed or hastened a decision to seek one is debated.
▸Israel is widely believed to hold Nuclear weapons and proliferationWidely agreed
The relationship
Israel is widely believed to have built nuclear weapons by the late 1960s at its Dimona reactor, built with French help. It neither confirms nor denies them, a policy called amimut ('ambiguity'), and has not joined the NPT. It also strikes rivals' programs: Iraq in 1981, Syria in 2007 and Iran in 2025–26.
Since when and why
The Negev Nuclear Research Center near Dimona, built from the late 1950s; former technician Mordechai Vanunu exposed it to Britain's Sunday Times in 1986.
How solid?
Vanunu's photographs, declassified US records of a 1969 Nixon–Meir understanding, and independent estimates of about 90 warheads; Israel gives no official confirmation.
What to watch
How many warheads it has, and whether ambiguity can last if Iran or Saudi Arabia pursue weapons; Arab states push for a Middle East zone free of nuclear arms.
▸Pakistan is armed with Nuclear weapons and proliferationFact
The relationship
Pakistan pursued the bomb after losing East Pakistan, now Bangladesh, in 1971 and after India's 1974 test. It tested in May 1998, weeks after India, and now has about 170 warheads, including short-range missiles meant to deter an Indian conventional attack. Scientist A.Q. Khan's network sold designs to Iran, Libya and North Korea.
Since when and why
Chagai Hills (May 28, 1998) and the Kharan Desert (May 30), both in Balochistan; Khan's network was exposed in 2004; India–Pakistan fighting in May 2025 revived nuclear fears.
How we know
Seismic records of the tests, Khan's 2004 televised confession, IAEA findings on Libya and Iran, and SIPRI warhead estimates.
What to watch
Whether Pakistan's September 2025 defense pact with Saudi Arabia extends its nuclear umbrella, which officials have hinted at and then played down.
▸China (People's Republic of China) is rapidly expanding its arsenal of Nuclear weapons and proliferationWidely agreed
The relationship
For decades China kept a 'minimum deterrent' of a few hundred warheads. Since about 2020 it has expanded fast, to about 600 warheads by 2025, building roughly 320 new missile silos and showing a full land, sea and air triad at its September 2025 parade. The Pentagon projects over 1,000 by 2030. China keeps a no-first-use pledge.
Since when and why
Silo fields near Yumen, Hami and Ordos, spotted by independent researchers in satellite images in 2021; Beijing's military parade of September 3, 2025.
How solid?
Commercial satellite imagery analyzed by the Federation of American Scientists and the Middlebury Institute, Pentagon annual reports and SIPRI estimates; China publishes no figures.
What to watch
Why China is expanding, to deter the US over Taiwan or to seek parity, and whether it will ever join arms-control talks, which it refuses while far behind.
▸North Korea (DPRK) keeps expanding Nuclear weapons and proliferationFact
The relationship
North Korea left the NPT in 2003 and tested nuclear devices six times from 2006 to 2017. It has an estimated 50 warheads and material for more, ICBMs such as the Hwasong-19, and a 2022 law allowing preemptive use. It calls its nuclear status irreversible and enriches uranium at more than one site.
Since when and why
Tests at Punggye-ri from 2006 to 2017; the Yongbyon reactor and enrichment plants; the Hwasong-19 ICBM test in October 2024.
How we know
Seismic data from the tests, satellite imagery of Yongbyon, state-media photos of Kim at an enrichment hall in 2024, and SIPRI estimates.
What to watch
Whether Russia now shares missile or submarine technology in return for troops, and whether a seventh nuclear test, long prepared at Punggye-ri, is coming.
▸Nuclear Non-Proliferation Treaty (NPT) aims to stop the spread of Nuclear weapons and proliferationFact
The relationship
The NPT is the main legal barrier to proliferation: non-nuclear members accept IAEA inspections and forgo weapons, while the five recognized nuclear states pledge disarmament talks. It has held most countries back, and in the 1990s South Africa, Ukraine, Belarus and Kazakhstan gave up weapons and joined as non-nuclear states.
Since when and why
Opened for signature on July 1, 1968, in force from March 5, 1970, extended indefinitely in 1995; review conferences every five years.
How we know
Membership records, IAEA safeguards reports, and the small number of nuclear states compared with 1960s predictions of many more.
What to watch
Whether a withdrawal by Iran, which has debated leaving, would trigger others in the Middle East, and whether the bargain holds as nuclear states expand.