Harvard Law Review: joining Nuclear Ban Treaty will not violate existing security agreements

June 19, 2018

New publications by the Harvard Law Review’s Human Rights Clinic show that existing security agreements for NATO countries and other US allies do not prevent states from joining the Treaty on the Prohibition of Nuclear Weapons.

With denuclearization firmly back on the international agenda after last week’s summit in Singapore, all responsible states should be joining the UN Treaty on the Prohibition of Nuclear Weapons (TPNW). But some countries have questioned whether joining the treaty would conflict with their pre-existing security agreements. Two new reports by Harvard Law Review’s Human Rights Clinic’s B. Docherty have found that there is no such conflict. Here are five highlights from the studies:

#1 Yes, states will have to step out from under the nuclear umbrella

The “nuclear umbrella” refers to military cooperation between at least two countries in which a nuclear-armed state agrees to protect a non-nuclear-armed state with nuclear weapons, and the non-nuclear-armed state ‘consents to, or acquiesces the potential use of unclear weapons in their defense.’ There are also several states that host nuclear weapons for nuclear-armed states as part of these defense treaties.

+ More about nuclear, host and endorsing states

Nations with nuclear weapons United States, Russia, Britain, France, China, Israel, India, Pakistan, North Korea
Nations hosting nuclear weapons Belgium, Germany, Italy, Netherlands, Turkey
Nations endorsing nuclear weapons Albania, Australia, Belarus, Bulgaria, Canada, Croatia, Czech, Denmark, Estonia, Greece, Hungary, Iceland, Japan, Latvia, Lithuania, Luxembourg, Montenegro, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, South Korea, Spain (plus the five host nations)

or read more here

By their very nature, all of these arrangements contravene the Nuclear Ban Treaty, because they depend on the continued existence of nuclear weapons. A state can’t base its security on its allies’ nuclear arms while being party to a treaty with the explicit goal of total elimination. According to Docherty, umbrella arrangements violate article 1(1)(e) and (f) which prohibits assisting – or seeking assistance-, encouraging or inducing anyone to possess, use, or threaten to use nuclear weapons.

That means that under the TPNW ‘umbrella states’ would have to reject any role for nuclear weapons within their security policies – including the threat of use on their behalf. But this does not mean these countries would have to leave long-standing security alliances…

#2 Stepping out of the nuclear umbrella wouldn’t violate existing agreements with nuclear-armed states (including NATO)

The TPNW does not require states to abandon existing security alliances with nuclear-armed states, and Docherty’s global review of nuclear umbrella arrangements found that collective security agreements generally do not pose insurmountable legal obstacles either. Nuclear umbrella arrangements are often political statements made outside security agreements, not legally binding commitments.

#3 Good news: The North Atlantic Treaty does not actually specifically require (supporting) nuclear weapons

A state that wishes to withdraw from the nuclear umbrella associated with NATO can do so without violating any legal obligations to the alliance, and would in fact have the full right to do so. Docherty found that The North Atlantic Treaty itself does not explicitly mention nuclear weapons, or specify the capacities states need to ‘separately and jointly … maintain and develop their individual and collective capacity to resist armed attack.”

This broad interpretation explains why several countries have already been able to adopt different positions on nuclear weapons: Denmark, Norway and Spain don’t allow nuclear weapons deployed on their territories during peacetime, Iceland and Lithuania don’t allow them even during conflict. Similarly, non-member countries with separate security agreements or partnerships are also free to dictate their own terms of agreements. In fact, Austria – a neutral country, but with existing NATO partnerships — recently became the ninth country to join the TPNW, and the Swiss First Chamber approved a motion to sign and ratify the treaty.

In a second article, Docherty looked specifically at Sweden, as an EU nation that has several security agreements with NATO and participates actively in joint military operations and peacekeeping missions with NATO members. Download the full case study here or read the highlights below:


#4 Yes, South Korea can and should leave the US nuclear umbrella (and Japan and Australia can too!)

Similarly to the North Atlantic Treaty, Docherty found that none of the collective security treaties that Australia, Japan and South Korea have signed with the US specifically reference nuclear weapons, or require these countries to accept nuclear umbrella arrangement as part of a defense strategy. Instead, their condition as umbrella countries comes from later – non-legally binding – political commitments or statements.

In the case of South Korea particularly, renouncing the nuclear umbrella and joining the TPNW could be an incredibly powerful first step towards the denuclearization of the Korean Peninsula. Joining the treaty would move the denuclearization process into the realm of multilateral UN-backed agreements. Find out more about our five-step roadmap for the denuclearization of the Korean Peninsula.

#5 No, the TPNW would not interfere with joint military operations with nuclear-armed states

In the case of joint military operations, Docherty concludes that participation in a joint operation with a nuclear-armed state does not in and of itself violate the TPNW. Based on the way other humanitarian disarmament treaties have been implemented, the biggest criteria to assess a violation would be the existence of a ‘nexus’ between the operation and the use of nuclear weapons.

For the Mine Ban Treaty, for instance: “a state party would violate the treaty if its troops assisted a state not party by fueling trucks carrying antipersonnel landmines or loading such trucks with mine. These activities would be unlawful because they supported a specific operation involving anti-personnel mines.” And perhaps an equally significant precedent: joint military operations with the US have continued despite the fact that the US has not yet joined the Mine Ban Treaty. In the Swedish case study, Docherty further breaks down how a country could determine the extent of their participation in military operations. “As long as Sweden does not change its activities in a way that would rise to the level of assistance, it could continue to contribute to such operations as a TPNW state party.”

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