To share or not to share: the compatibility of NATO’s nuclear sharing arrangements with the Non-Proliferation Treaty

Nuclear sharing on the NPT RevCon

On 27 April 2026, States will collect in New York for the beginning of the Eleventh Overview Convention of the Non-Proliferation Treaty (NPT). The ‘RevCon’ comes at a very turbulent second in time, marked by nuclear saber-rattling by Russia within the context of its battle of aggression towards Ukraine, a fast enlargement of China’s nuclear arsenal, and renewed ballistic missile launches by the DPRK, to not point out the controversy over Iran’s nuclear programme culminating in US-Israeli assaults towards Iran’s nuclear amenities. In the meantime, the US accused China of clandestinely conducting low-yield nuclear explosive checks, suggesting it might resume nuclear testing ‘on equal foundation’, whereas France just lately offered a brand new coverage of “dissuasion avancée” (ahead deterrence).

All these parts make for a tense geopolitical setting and a diplomatic quagmire. Whether or not the Vietnamese RevCon President will fare any higher than his two predecessors in securing an agreed final result doc by the top of the convention in late Might stays to be seen.

One matter that has risen to higher prominence within the run-up to the RevCon issues the ‘nuclear sharing preparations’ (NSAs) between the US and a number of other European NATO Allies. Professional memorie, beneath the NSAs, america has deployed a restricted variety of B-61 nuclear weapons to sure places in Europe (whereas no official determine is revealed, the entire would look like however a small fraction of the variety of non-strategic nuclear weapons deployed in Europe by Russia).

Lately, a rising group of States from the International South has denounced the NSAs as incompatible with the NPT. Critique of the NSAs has hardened, and brought a extra ‘legalistic’ tone (see e.g. right here).

In gentle hereof, this submit examines the authorized arguments raised towards the NSAs, and submits that they’re in the end unconvincing. Inasmuch because the ‘unusual that means’ of the important thing NPT provisions provides no conclusive reply, we focus as a substitute on different interpretative parts that would seem related beneath Articles 31(3)(b) and 32 of the Vienna Conference on the Legislation of Treaties (VCLT), particularly the NPT’s travaux, in addition to subsequent follow following its entry into drive.

A more in-depth take a look at Articles I-II NPT

Pursuant to Article I of the NPT, “[e]ach nuclear-weapon State Occasion to the Treaty undertakes to not switch to any recipient in any way nuclear weapons … or management over such weapons … straight, or not directly; and never in any solution to help, encourage, or induce any non-nuclear-weapon State to fabricate or in any other case purchase nuclear weapons …, or management over such weapons …”. Article II NPT conversely obliges non-nuclear-weapon States to not “obtain” such management or help. The notions of “switch” or “management” are usually not additional outlined within the treaty.

NATO Allies have persistently maintained that the NSAs don’t entail a prohibited ‘switch’ of (management over) a nuclear weapon within the sense of Articles I-II NPT because the weapons involved stay beneath full US custody and management. Additional, inasmuch because the NSAs have eliminated the motivation for different European nations to pursue a nuclear arsenal of their very own, quite than undermining the ‘object and objective’ of the NPT, they’re deemed as a substitute to advertise non-proliferation. Past these interpretive arguments drawn from the ‘unusual that means’ of the textual content in addition to the Treaty’s ‘object and objective’, reference can be made to the Treaty’s travaux and the context of its birthing course of.

The genesis of Articles I and II NPT: a US-Soviet compromise

It’s well-known that the US and the USSR acted as pen-holders in drafting Articles I and II. Inside the Eighteen-Nation Disarmament Committee (ENDC), the 2 nations initially tabled radically completely different proposals. Particularly, the US draft left room for types of joint possession and collective management over a strategic nuclear system involving each nuclear-weapon States and non-nuclear-weapon States – choices that have been excluded beneath the Soviet  draft.

Discussions came about at a time when the US and different NATO Allies sought to formalize nuclear session and planning within the NATO context – a course of that may culminate within the creation of the Nuclear Planning Group (NPG) in December 1966. Initially, nonetheless, extra bold proposals centered across the creation of a NATO ‘Multi-Lateral Nuclear Pressure’ (MLF) or an ‘Atlantic Nuclear Pressure’ (ANF), with situations together with, as an example, the manning of collectively funded weapon methods by mixed-nationality crews from completely different NATO members. The creation of a NATO nuclear drive was, nonetheless, strongly resisted by the Soviet Union, specifically out of worry that Germany might acquire entry to nuclear weapons. 

The deadlock was in the end resolved by means of behind-the-scenes discussions between the US and the USSR. Upon instruction of the respective international ministers, a joint working group was arrange in October 1966 to organize a draft treaty. Declassified transcripts of the conferences affirm that the USSR was made conscious of the US place that it could not comply with any textual content which might rule out NATO NSAs.  

Following arduous negotiations, the 2 superpowers in the end arrived at a compromise within the type of a joint draft concurrently submitted by the US and the USSR, which deserted references to ‘entry’ or ‘emplacement’ – phrases that had featured within the preliminary Soviet draft -, as a substitute specializing in direct or oblique ‘management’ over nuclear weapons. Within the phrases of US negotiator George Bunn (right here at p. 39): 

“We received removing of Soviet language… that threatened to embarrass each NATO nuclear consultations and two-key preparations. The Soviets received language banning transfers by means of a gaggle of States.”

Earlier than the joint draft was formally submitted to the ENDC in 1967, the US co-chair shared together with his Soviet counterpart a set of Q&As which the US had beforehand offered to NATO Allies to tell them of the end result of the US-Soviet negotiations. This doc, which might later floor within the proceedings earlier than the US Senate, asserted that the NPT “doesn’t take care of allied consultations and planning on nuclear protection as long as no switch of nuclear weapons or management over them outcomes”, and “doesn’t take care of preparations for deployment of nuclear weapons inside allied territory so long as these don’t contain a switch of nuclear weapons or management over them”.

In his authoritative research of the NPT negotiating historical past, Mohammed Shaker equally concludes that the US-Soviet compromise resulted in “the dropping of the multilateral choice by america. In return, the Soviet Union dropped its insistence on discontinuing the already current nuclear-sharing preparations” (see Vol. I at 233). Based mostly on comparable analyses of the NPT’s negotiating historical past, many students agree that the language of Articles I and II was not drafted with the intention of prohibiting nuclear-sharing preparations (see e.g. Hayashi, at 475).

Within the margin, an oft-overlooked level is that the Soviet Union might itself have had an curiosity in ‘containing’ the scope of the 2 provisions, as proof means that the USSR additionally deployed nuclear weapons in jap Europe within the context of the Warsaw Pact (see e.g. right here, at 214). It follows that Moscow’s negotiating posture might have been pushed much less by a principled objection to all types of nuclear deployment overseas, and extra by a want to constrain Western preparations with out foreclosing its personal strategic flexibility.

Et alors?

One would possibly in fact object that any pact between the 2 Superpowers – particularly one arrived at behind closed doorways – as to the interpretation of Articles I and II NPT can hardly be taken to replicate the settlement of all States events, and accordingly can’t be opposable to different States. Critics of the NSAs have certainly recommended that, throughout the NPT negotiations, third nations have been left within the blind, each with respect to the nuclear sharing preparations themselves, in addition to with the US-Soviet settlement to not exclude such preparations by means of Articles I-II NPT (see right here, at 16-18). A more in-depth take a look at the travaux nonetheless reveals a starkly completely different image.

What classes from the ENDC and UNGA First Committee information?

First, it’s clear that the existence of the NSAs and their most important options have been well-known by the members of the ENDC, and by UN Members extra broadly. On numerous events, the US defined that it retained “affirmative management” over its nuclear weapons deployed in Europe “always” (right here, at 21); that session with NATO Allies didn’t entail giving non-nuclear weapon States info “on the best way to manufacture nuclear weapons” (right here, at 20); and that management was ensured i.a. by means of “complicated codes and digital gadgets which forestall any unauthorized motion” (right here, at 14). And elsewhere: “[l]ike the Soviet Union’s Warsaw Pact allies, United States allies do obtain coaching in dual-capability weapon methods… Nevertheless, United States nuclear weapons stay firmly in United States palms” (right here, at 14).

Second, because the US and USSR offered their drafts of what would later turn out to be Articles I and II, third States have been totally conscious of the significance of the difficulty. As an illustration, contemplating the completely different formulations within the preliminary drafts, Mexico referred to this as the actual “crux proliferationis” (right here, at 8), whereas Burma famous how the query of “nuclear-sharing preparations inside navy alliances” constituted one of many most important bones of competition within the negotiations (right here, at 19, para. 52). A number of States urged the 2 powers to work out a compromise between themselves and/or responded positively when bilateral negotiations produced a joint draft. India, for one, welcomed that “there may be settlement now between the 2 alliances on the query of nuclear-sharing preparations” (right here, at 30, para. 79).

Third, and most essential, numerous States confirmed that the NPT didn’t prohibit nuclear sharing. For instance, Mexico said that the draft treaty was “solely designed to ensure that the variety of States having nuclear weapons of their territory or management shall not be elevated, however with out in any method limiting the capability of the current nuclear Powers to put in or emplace nuclear weapons within the territories of different States” (right here, para. 79). Each within the ENDC and within the UNGA First Committee, some States expressed remorse that the NPT didn’t prohibit the deployment of nuclear weapons on the territories of non-nuclear weapon States, and didn’t forestall the coaching in the usage of nuclear weapons of the armed personnel belonging to these non-nuclear weapon States (see e.g. India (right here, para. 27 and right here, para. 115); Algeria (right here, para. 68); Uganda (right here, para. 49), and; Mauritius (right here, at 202) – for an remoted counter-example see Nigeria (right here, para. 54)). Romania even – unsuccessfully – tabled a proposal of its personal, not a lot to ban nuclear sharing, however quite to introduce a system of verification by means of the UN Safety Council (right here, para. 13). Crucially, the expressions of remorse didn’t cease these nations from in the end signing and ratifying the NPT – in full information that nuclear sharing wouldn’t be banned.

Subsequent follow: studying the leaves

Leaving apart the NPT’s travaux, what classes could be gleaned from the next follow within the utility of the Treaty? In fact, latest PrepComs and RevCons reveal that  numerous States criticize nuclear sharing as opposite to the Treaty’s spirit (e.g. Brazil, South Africa) or as a plain violation (e.g. Brazil, Egypt, Iran). Earlier RevCons nonetheless inform a unique story.

For starters, on the first RevCon in 1975, a gaggle of 5 States launched a draft decision (see right here) ‘inviting’ negotiations on a brand new treaty that would supply for the withdrawal of nuclear weapons from the territories of non-nuclear weapons States Events. If this demarche absolutely displays dissatisfaction with nuclear sharing practices, it implicitly confirms such practices weren’t taken to contravene current obligations beneath the NPT. The proposal itself was by no means adopted. Au contraire, States Events as a substitute  adopted a Ultimate Declaration confirming that “the obligations undertaken beneath Article I and II of the Treaty have been faithfully noticed by all Events” (right here, Annex 1, at 2). 

Questions pertaining to the compatibility of NATO’s NSAs solely first emerged on the 1995 RevCon. Considerably sarcastically, it seems that the primary to boost the matter was Mexico – nota bene one of many unique ENDC members, which had acknowledged all through the negotiations that the NPT didn’t prohibit nuclear sharing (see above). Whereas round eight different nations adopted swimsuit, a number of tended to problem the NSAs in quite ambiguous phrases – Tanzania, as an example, famous, considerably circularly, that “the deployment of nuclear warheads within the territory of non-nuclear-weapon States would characterize a violation of Article I if it was interpreted as a switch of nuclear weapons” (see right here, para. 24 – our emphasis). In flip, a number of NATO Allies responded by asserting that NATO’s NSAs complied strictly with the NPT, with Germany, as an example, stressing that “at no Convention of the Events had there ever been any criticism that these agreements contravened articles I and II of the Treaty” (see right here, para. 20). What’s extra, quite than becoming a member of the nascent refrain of critics, Russia – co-author of the unique treaty textual content – seems to not have expressed any view on the difficulty. It could take till 2015 – lengthy after the removing of Soviet nuclear weapons from jap Europe – for Russia to shift sides and brazenly problem the NSAs (see right here).

In the end, States Events agreed on the 1995 RevCon to the indefinite extension of the NPT with out reopening or modifying the wording of Articles I-II, or in any other case clarifying their interpretation, at a second that may have been notably opportune to articulate issues concerning the interpretation of the NPT’s core non-proliferation provisions. 

The image that emerges is that criticism of the NSAs on the 1995 RevCon can solely be seen as “too little, too late” – and an analogous statement essentially holds true for the extra express and widespread criticism in more moderen years. Certainly, from the angle of treaty interpretation, such criticism can’t offset the negotiating historical past of the NPT, NATO’s decades-long nuclear sharing follow, and the constant opposition of NATO Allies towards any studying of Articles I and II NPT departing from the unique US-Soviet compromise.

Turning again the clock? 

This submit has sought to have interaction with the criticism that NATO’s NSAs run afoul of the NPT by retracing the origins of the important thing NPT provisions, in addition to their remedy on the early RevCons. Our evaluation in the end helps the conclusion of Boothby and von Heinegg (amongst others) that “NATO’s sharing preparations for basing US nuclear gravity bombs in Europe are in compliance with the NPT” (right here at para. 1.123).

This isn’t to say that every one is rosy within the land of non-proliferation, in fact. Even when the entire variety of US nuclear weapons stationed on European soil could also be solely a fraction of what it as soon as was, worldwide verifiable elimination of nuclear weapons in accordance with Article VI NPT stays far off. But, quite than investing time and power in a revisionist effort to show again the clock on the interpretation of Articles I-II NPT, the RevCon’s momentum provides States a possibility to discover significant progress on nuclear disarmament and risk-reduction.

*The current weblog submit in written within the authors’ private capability.