The prohibition on threatening to use
The Nuclear Weapons Ban Monitor found that one state acted in contravention of the TPNW’s prohibition on threatening to use nuclear weapons in 2023: North Korea. That is not to downplay the many nuclear threats articulated by various actors in Russia throughout the year, but they did not constitute threats to use under international law as they did not emanate from a person or an authority in a position to either direct or authorise the use of nuclear weapons.
When North Korea in August 2023 fired two short-range ballistic missiles to simulate nuclear strikes on military targets in South Korea, state media said the tests were held as a 'warning' against the US deployment of strategic bombers to the region. The media referred to a statement issued by the North Korean army, that said: ‘The drill is aimed to send a clear message to the enemies’ who ‘challenge us with such military threats as the deployment of strategic nuclear assets despite our repeated warnings.’
Explicit threats to use nuclear weapons by the leader of a nuclear-armed state are rare. More often, threats are made by people close to but not in government. President Vladimir Putin and Foreign Minister Sergey Lavrov toned down their nuclear rhetoric in 2023, and the military leadership remained largely silent on the issue. Multiple nuclear threats, however, were made in the context of the war in Ukraine by lower level Russian officials and media personalities. The alarming frequency of statements regarding use of nuclear weapons could of course be indicative of Putin’s endorsement, but nonetheless they do not constitute threats to use under international law because they were not made by the leadership of the state.
The International Campaign to Abolish Nuclear Weapons (ICAN) warns that aggressive nuclear rhetoric and threats are normalising the idea of using nuclear weapons and that it is vital to consistently and categorically condemn any and all threats to use nuclear weapons. TPNW states parties and signatories such as Brazil, Indonesia, Mexico, and South Africa continued in 2023 to work to delegitimise nuclear weapons in forums like G20, and their efforts had an impact. The G20 New Delhi Leaders’ Declaration reiterated that the use and threat of use of nuclear weapons is ‘inadmissible’.
For more information, see the 2023 edition of the Nuclear Weapons Ban Monitor.
Each State Party undertakes never under any circumstances to ‘threaten to use nuclear weapons or other nuclear explosive devices’.
- Article (1)(1)(d) prohibits threatening to use a nuclear weapon or other nuclear explosive device at all times, and regardless of whether such use would itself be a violation of international law or in legitimate self-defence against foreign aggression. It is therefore broader in scope than the prohibition on threat of force in Article 2(4) of the UN Charter.
- To violate the TPNW, a threat of use must be credible in the circumstances. This means that the threat must emanate from a person or an authority in a position to either direct or authorise the use of a nuclear explosive device. Typically, therefore, such a threat would be made by a senior (and pertinent) government official or leading member of the ruling party in a nuclear-armed state.
- The narrow wording in Article 1(1)(d) of the TPNW with the active verb ‘threaten to use’ requires that any signalled intention by a state to use nuclear weapons be specific as to the target of threatened use.
- Prohibited threats may, however, be implicit as well as explicit. A stated threat does not, therefore, have to refer to use of nuclear weapons, although it would be more likely to violate thenorm in the TPNW should it do so.
- In certain circumstances of tension, a show of force by means of missile testing, an explosive test of a nuclear weapon, a military exercise involving possible use of nuclear weapons, or a nuclear strike exercise, could amount to unlawfully threatening to use nuclear weapons under the TPNW (along with other violations of the Treaty).
- Policies of nuclear ‘deterrence’ rest on willingness to use nuclear weapons. Accordingly, reflecting the severity of the danger, some experts take the view that a practice of nuclear ‘deterrence’ in and of itself constitutes an unlawful threat of use of nuclear weapons. It is the view of the Nuclear Weapons Ban Monitor that the broader concept of nuclear deterrence, where the threat to use nuclear weapons is general and not specific in nature, is not sufficient in itself to constitute threatening to use under the TPNW. Deterrence practices are, however, illegal under the prohibition on possession and stockpiling.
- The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) does not prohibit the threat of use of nuclear weapons.