The Netherlands have been a member of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) since 1970. This treaty represents the most important multilateral agreement related to nuclear weapons. The Netherlands are a non-nuclear-weapon state party to the NPT and thus may not possess any nuclear weapons. As Article 2 of the Treaty states:
“Each non-nuclear-weapon State Party to the Treaty undertakes not to receive the transfer from any transferor whatsoever of nuclear weapons or other nuclear explosive devices or of control over such weapons or explosive devices directly, or indirectly; not to manufacture or otherwise acquire nuclear weapons or other nuclear explosive devices; and not to seek or receive any assistance in the manufacture of nuclear weapons or other nuclear explosive devices.”
United Nations, Office for Disarmament Affairs
The stationing of foreign nuclear weapons on the territory of a non-nuclear-weapon state is controversial at the international level. NATO allies understand the NPT to mean that the stationing of weapons in other countries is legal, provided the possessing state controls the weapons. Nuclear weapons were already stationed in the Netherlands before the treaty negotiations began. Before it entered into force, the NATO allies set out their interpretation of the NPT:
“The treaty does not in itself prohibit the stationing of nuclear weapons on the territory of non-nuclear-weapon states.”
Explanatory memorandum on the approval of the Treaty on the Non-Proliferation of Nuclear Weapons, July 1, 1968, p.14
However, this view is not shared by all parties to the NPT. Many states regularly criticize the practice of nuclear weapon sharing. The group of non-aligned countries (120 countries outside of NATO and the former Warsaw Pact) issued the following statement during a review conference of the NPT:
“In our view, any horizontal proliferation and nuclear-weapon-sharing by States Parties constitute a violation of non-proliferation obligations under articles I and II.”
Statement by the non-aligned movement, April 27, 2015
A use of nuclear weapons, in which Dutch pilots would gain power of disposal over stationed nuclear weapons, would constitute a breach of the NPT. International treaties usually retain their validity even in the event of war (for example, the Geneva Convention, or other classic arms control treaties such as the conventions on chemical and biological weapons).
The new Treaty on the Prohibition of Nuclear Weapons (TPNW), which entered into force on January 22, 2021, provides legal clarity on the stationing issue. This treaty explicitly prohibits its parties from hosting foreign nuclear weapons (Article 1.1.g). The Netherlands is not a party to this treaty, so it is not currently bound by the prohibition. However, the Netherlands was the only NATO state participating in the negotiations of the treaty (although it voted against its adoption), and it attended as an observer the first meeting of states parties (MSP1) of the TPNW. Subsequently, the Dutch Ministry of Foreign Affairs informed the parliament that continued participation would “not make sense”. Consequently, the Netherlands refrained from attending the second meeting of states parties (MSP2) in 2023.
Numerous states in the Global South have long been members of regional nuclear-weapon-free zones that prohibit the stationing of nuclear weapons on land. Regulations on overflight and transit through territorial waters vary from region to region.
Bilateral agreements between the United States and the Netherlands regulate the stationing of US nuclear weapons on Dutch soil. The contents of the agreements are secret, however. Indeed, the government largely ignored a motion by the Dutch parliament (passed with 94 to 56 votes) to allow the examination of the bilateral treaties between the United States and the Netherlands relating to nuclear deployments, as according to the government, it would be forbidden by Dutch law to disclose them. An official US report lists four different agreements: an Atomic Stockpile Agreement, an Atomic Cooperation Agreement, a Service-Level Agreement and a Third-Party Stockpile Agreement.
From 1959 onward, several technical agreements were signed between the Netherlands and the United States concerning the deployment of nuclear weapons. Different agreements covered the deployment of ground launched nuclear weapons, air delivered nuclear weapons deployed to Volkel Air Base, and the earmarking of nuclear weapons in Germany for Dutch forces in Germany. In addition, a further technical agreement was signed between the U.S. Navy and the Dutch Navy in 1968, and between the Dutch Navy and the British Navy in 1970, to permit Dutch Neptune aircraft and later P-3 Orion aircraft stationed at Valkenburg Air Base to deploy nuclear depth bombs stored in the United Kingdom at St. Mawgan. Interestingly, starting with the Murphy-Dean agreement, the Americans have confirmed in numerous letter exchanges that the British would be consulted before any use of nuclear weapons from their territory. In 1965, US President Johnson confirmed to his British counterpart that this right also extended to the Dutch earmarked weapons deployed at St. Mawgan. However, there is no indication of a similar consultation agreement with the Netherlands. Indeed, during the early stages of the Cold War, the United States concluded to have the right to unilaterally deploy nuclear weapons from Dutch territory. It is also known that NATO has assigned code words to the specific Service-Level Agreements for each nuclear host state. The Dutch is referred to as “Toy Chest”.
The fundamental legality of nuclear weapons use was discussed and reviewed by the International Court of Justice in The Hague in 1996. The judges concluded that the use of nuclear weapons would be incompatible with international humanitarian law in the vast majority of scenarios. Extreme self-defense situations represented the only use case excluded in the judgment. According to the court, international humanitarian law was not specific enough, so that the judges had to leave the question of legality or illegality open.