Under my umbrella

ILPI Publications > Background Papers

Understanding the terms ‘nuclear umbrella’ and ‘nuclear umbrella state’

5 August 2016

The term ‘nuclear umbrella’ is frequently used to describe military alliances that maintain the option of using nuclear weapons in their collective defence. Yet despite its widespread use, the concept lacks a precise definition, and there does not seem to be agreement on exactly which states should be referred to as ‘nuclear umbrella states’.


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In an attempt at nuancing the conceptual landscape and providing a working definition of the term, this background paper takes a closer look at some of the military alliances that have been labelled ‘nuclear umbrellas’. In so doing, we make three main points:

  • First, there is considerable variation in the degree to which existing nuclear umbrellas are formalised in written documents. While the nuclear aspects of some alliances have been agreed and adopted at the highest policy level—such as NATO—the nuclear aspect of other alliances—such as that between Australia and the United States—are based on an unwritten mutual understanding.
  • Second, regardless of whether or not the nuclear policy doctrine is written down, none of the nuclear umbrellas currently in existence should be mistaken for legally binding arrangements. Granted, the nuclear doctrines usually occur as a supplement or in parallel to a legally binding mutual defence treaty, but none of those underlying treaties deal specifically with nuclear weapons. A nuclear umbrella should, therefore, be understood as a political construct.
  • Third, the mere existence of a collective security agreement between a nuclear-armed and a non-nuclear-armed state does not automatically produce a nuclear umbrella. Due to the nature of the weapons, and the doubt and uncertainty surrounding any conceivable decision to use them, one should assume that the existence of a nuclear umbrella must be accepted both by the extender and the receiver of the nuclear-weapon-based security guarantee before the security arrangement in question is counted as a nuclear umbrella.

This paper is divided into two main sections. In the first section we go through some of the nuclear-armed military alliances in existence today, with the aim of identifying common parameters and features. In the second section, we analyse and systematise these elements with a view to exploring the theoretical boundaries of the concept, and ultimately to arrive at a working definition.

Military alliances with nuclear weapons

In theory, all the nine nuclear-armed states in the world could extend nuclear security guarantees to whichever states they choose. But in practice, only a few of them do. Russia is presumed to be willing and able to use any means necessary, nuclear weapons included, in order to defend its closest allies—notably the members of the Collective Security Treaty Organization (CSTO). Yet by far the most far-reaching web of existing nuclear security guarantees, however, is extended by the United States in the form of bilateral agreements in the Pacific and through the North Atlantic Treaty Organization (NATO).


NATO is often described as a ‘nuclear alliance’.[i] Yet NATO’s founding (and only legally binding) document, the 1949 North Atlantic Treaty, does not refer to nuclear weapons. In fact, the nuclear aspect of the alliance went unspecified until the adoption of the alliance’s third Strategic Concept, in 1957. According to that document, NATO would, if the Soviet Union decided to invade, ‘be unable to prevent the rapid overrunning of Europe unless NATO immediately employed nuclear weapons both strategically and tactically’. Therefore, NATO would have to ‘be prepared to take the initiative in their [nuclear weapons’] use.’[ii]

According to NATO’s own website, the Strategic Concept is an ‘official document that outlines NATO’s enduring purpose and nature and its fundamental security tasks’. The document ‘also identifies the central features of the new security environment, specifies the elements of the Alliance’s approach to security and provides guidelines for the adaptation of its military forces’.[iii] Having been unanimously adopted at the highest political level, the document carries significant weight as a policy roadmap. It lays down a set of specific commitments, which would be politically uncomfortable to disregard. It is not, however, a legally binding document.

Since the 1950s, the United States has maintained nuclear weapons in allied countries, including several NATO member states. To this day, nuclear weapons remain stationed in five non-nuclear-armed NATO states: Belgium, Germany, Italy, Netherlands, and Turkey. The policy of ‘forward deployment’ of nuclear weapons has been controversial from the start, including within the alliance. At the NATO summit in Paris in 1957, when the practice was formally introduced as NATO policy, the prime ministers of Denmark and Norway expressed strong opposition. Today, several NATO states, including Lithuania, Spain, and the three Nordic NATO members, have explicit policies against hosting nuclear weapons on their territory.[iv] At the same time, all of NATO’s member states except France participate in NATO’s Nuclear Planning Group—the alliance’s forum for discussing nuclear strategy.

NATO’s latest Strategic Concept, adopted in 2010, states that ‘as long as there are nuclear weapons in the world, NATO will remain a nuclear alliance.’[v] Yet the document also makes clear that NATO is committed to creating ‘the conditions for a world without nuclear weapons in accordance with the goals of the Nuclear Non-Proliferation Treaty.’[vi] By emphasising the need for ‘creating conditions’ for disarmament rather than actually ‘pursuing negotiations in good faith’—which is what the Nuclear Non-Proliferation Treaty (NPT) requires[vii]—the Strategic Concept stops short of restating the legally binding obligation that all of its member states have under the NPT. At the same time, the inclusion of this sentence was seen as progress for NATO’s arms control and disarmament agenda, as it was the first time the Strategic Concept articulated the goal of a world free of nuclear weapons.

The latest communiqué from NATO leaders—adopted in Warsaw in 2016—was considered by many as a step back in this regard,[viii] but all in all, the nuances of the language in these policy documents do not alter the fact that NATO is a declared nuclear umbrella, and that­ in theory­ the nuclear-armed members of the alliance have pledged to stand by their allies in times of crises—even if it means using nuclear weapons.

United States—Australia

The United States is commonly understood to extend a nuclear umbrella over Australia. This umbrella is rooted in the Australia, New Zealand, United States Security Treaty (commonly known as the ANZUS Treaty), which states that each of the parties ‘recognises that an armed attack in the Pacific Area on any of the Parties would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional processes.’[ix] As with the North Atlantic Treaty, the ANZUS Treaty contains no reference to nuclear weapons. Nevertheless, the agreement has been interpreted as a basis for the policy of extended nuclear deterrence, including a right for US ships and submarines armed with nuclear weapons to visit allied ports. In the mid-1980s, when the South Pacific Nuclear-Weapon-Free-Zone Treaty (‘Rarotonga’) was adopted—to which both Australia and New Zealand are parties—New Zealand proclaimed that it did not welcome visits by nuclear-armed vessels. [x] This led the United States to unilaterally suspend its treaty obligations towards New Zealand, who nevertheless remains a party to the ANZUS Treaty. Australia has not adopted a similar policy of refusing nuclear-armed vessels.

In contrast to NATO, ANZUS has no strategic concept stipulating the nuclear aspects of the alliance. Rather, the nuclear element of the security arrangement between the United States and Australia is based on a shared understanding between policy makers in Australia and the United States that their security cooperation includes the potential use of nuclear weapons. This understanding has been confirmed by officials (primarily Australian) on several occasions. One such confirmation can be found in a selection of official defence ministry talking points from 2013 on ‘nuclear weaponry’, which stated that ‘for so long as nuclear weapons exist, [Australia is] able to rely on the nuclear forces of the United States to deter nuclear attack on Australia.’[xi] On the part of the United States, proof of their willingness to defend partners and allies around the world can also be found in the Nuclear Posture Review of 2010, which states that the United States will ‘[…] reinforce security commitments to allies and partners by maintaining an effective nuclear umbrella […]’.[xii]

United States—Japan

Japan is covered by the United States’ nuclear umbrella much in the same way as Australia. While the 1960 Treaty of Mutual Cooperation and Security between the United States and Japan (commonly known as ‘Anpo’) does not specifically mention nuclear weapons, the policy of extended nuclear deterrence to Japan has been confirmed regularly by both sides, with a joint statement by US and Japanese defence and foreign ministers in 2013 as a recent example:

On the occasion of this historic meeting, the [Security Consultative Committee] reaffirmed the indispensable role our two countries play in the maintenance of international peace and security and reconfirmed our Alliance’s commitment to the security of Japan through the full range of US military capabilities, including nuclear and conventional.[xiii]

A controversial aspect of the Anpo Treaty is that it gives the United States a right to establish military bases in Japan.[xiv] It is not believed that US nuclear weapons have ever been permanently stationed on Japanese soil, yet it is likely that, pursuant to the United States’ don’t-ask-don’t-tell policy, nuclear weapons have been (or may still be) present in Japan.

United States—South Korea

The US nuclear umbrella over South Korea emanates from the security treaty concluded between the two countries following the end of the Korean War in 1953.[xv] This treaty specifies that the parties will ‘take suitable measures’ in order to defend each other from external armed attacks, but with no reference to nuclear weapons. In 2009, however, US President Barack Obama and South Korean President Lee Myung-bak issued an ‘alliance vision’ following a summit meeting in Washington. According to this document, the parties shall ‘maintain a robust defense posture, backed by allied capabilities which support both nations’ security interests. The continuing commitment of extended deterrence, including the US nuclear umbrella, reinforces this assurance.’[xvi]

Despite this explicit nuclear security assurance, South Korean officials appear to be less and less confident that the United States will protect South Korea in the event of an open conflict between North and South Korea. The United States supposedly stationed nuclear weapons on South Korean soil between 1958 and 1991, and some senior South Korean politicians have called for these to be redeployed, or alternatively for the development of an independent South Korean nuclear weapons programme.[xvii]


The Collective Security Treaty Organization (CSTO) is a military alliance comprised of Armenia, Belarus, Kazakhstan, Kyrgyzstan, Russia, and Tajikistan. While the organization itself was set up in 2002, the treaty on which it is based, the Collective Security Treaty or ‘Tashkent Treaty’, was adopted in 1992. The Tashkent Treaty stipulates in Article 4 that ‘[i]f one of the Member States undergoes aggression […] it will be considered by the Member States as aggression […] to all the Member States of this Treaty.’[xviii] As in the case of the treaties discussed above, the Tashkent Treaty does not mention nuclear weapons. Nor have the parties made public any policy document specifying the nuclear aspects of their collaboration. Russia does, however, have a nuclear doctrine similar to that of the United States, in which it reserves the right to use nuclear weapons to defend its allies.[xix]

And, in 2010, the CSTO Secretary General Nikolay Bordyuzha announced that Moscow’s nuclear umbrella had been extended to all of the CSTO member states.[xx] This assertion does not appear to have been contradicted by any of the CSTO member states, but nor has the policy been officially confirmed, either by the Kremlin or by any of the CSTO member states.[xxi]

At the time of the above-mentioned statement by the CSTO Secretary General, four of the CSTO member states were parties to the Central Asian Nuclear-Weapon-Free Zone (Treaty of Semipalatinsk).[xxii] Its protocol on negative security assurances was delayed from entering into force because Britain, France, and the United States refused to ratify it. The question was this: if the CSTO is a nuclear umbrella, how could four of its member states at the same time be members of a nuclear-weapons-free zone?[xxiii] (a question that also applies to Australia). The issue was solved following lengthy discussions about the meaning of Article 12 in the Treaty of Semipalatinsk, which states that the Treaty should not affect rights and obligations of the parties under treaties they had previously entered into. The nuclear-weapon states finally signed the Semipalatinsk protocol on negative security assurances in 2014. All of them, except the United States, have also ratified the protocol, though with reservations added by France and the UK. This long back-and-forth over the protocol on negative security assurances to the Central Asian Nuclear-Weapon-Free Zone indicates that the CSTO has indeed been interpreted as constituting a nuclear umbrella.

Other possible nuclear umbrellas

In addition to the three cases of bilateral US military alliances mentioned above (Australia, Japan, and South Korea), questions have sometimes been raised as to whether the American nuclear umbrella also extends to countries such as Thailand, the Philippines, and Taiwan.

United States—Thailand/Phillippines

Thailand and the Philippines both have formal security agreements with the United States. The language of these treaties is very similar to that of the treaties the United States has with Australia, Japan, and South Korea, albeit less committing than what is found, for instance, in Article 5 of the North Atlantic Treaty. Moreover, the United States has not issued explicit nuclear security guarantees to these countries, and neither Thailand nor the Philippines have expressed an expectation, or declared the existence, of such guarantees. On the contrary, the Philippines have in fact outlawed nuclear weapons in their constitution, and have specifically prohibited nuclear weapons on their territory—a policy also reflected in the 2014 Enhanced Defense Cooperation agreement between the US and Philippines.[xxiv] Moreover, both countries are parties to the Southeast Asian Nuclear Weapon-Free Zone Treaty (Treaty of Bangkok).

United States—Taiwan

For Taiwan, the situation is somewhat different. Up until 1978, the United States explicitly extended its nuclear umbrella over the island, and regularly patrolled the Taiwan Strait.[xxv] However, in a move to improve relations with mainland China, the United States abrogated the security treaty with Taiwan, and adopted the Taiwan Relations Act (TRA) instead. [xxvi] But the TRA is not a legally binding security agreement that commits the US to defend Taiwan, and the US is no longer expected to defend Taiwan with nuclear weapons, should it come to that. In the event of a crisis, the TRA only requires the US Government to report on the situation to Congress.[xxvii]


Another case of a possible nuclear umbrella relates to China and Ukraine. In early December 2014, Ukrainian President Viktor Yanukovych and Chinese President Xi Jinping signed a bilateral treaty. Their joint statement was said to contain the following passage:

China pledges unconditionally not to use or threaten to use nuclear weapons against the nuclear-free Ukraine and China further pledges to provide Ukraine nuclear security guarantee when Ukraine encounters an invasion involving nuclear weapons or Ukraine is under threat of a nuclear invasion. [xxviii]

According to other commentators, however, this translation is wrong, and what the statement really says is this:

“China pledges unconditionally not to use or threaten to use nuclear weapons against non-nuclear Ukraine, and under the conditions of Ukraine suffering an invasion using nuclear weapons or suffering the threat of this kind of invasion, to provide Ukraine with relevant security guarantees.” [xxix]

This language is quite similar to that used in UN Security Council Resolution 984 (1995), concerning negative security assurances. This suggests that the commitment expressed by China would apply to all countries, not just Ukraine, though the resolution does not mention the word ‘guarantees’, as used in the joint statement by China and Ukraine. It remains unclear, however, the extent to which China would be willing to use nuclear weapons to defend an attack on Ukraine. The joint statement does not constitute a legally binding agreement.


Defining a nuclear umbrella

There seems to be little disagreement about the fact the United States has extended an ‘Atlantic’ nuclear umbrella over the member states of the North Atlantic Treaty Organization (NATO), and a ‘Pacific’ nuclear umbrella over Australia, Japan, and South Korea.[xxx]

In addition, some commentators maintain that the members of the Collective Security Treaty Organization (CSTO) are covered by a Russian nuclear umbrella.[xxxi] As the above discussion underlines, however, this is by no means clear-cut. Does the existence of a nuclear umbrella require an explicit recognition of the nuclear option by one or more of its members? Or could its existence be inferred by the mere presence of a legally binding agreement on collective security involving one or more nuclear-armed states, as long as the nuclear option is not explicitly rejected?

One could argue that a nuclear umbrella should not simply be a by-product of a military alliance involving one or more nuclear-armed states. The United States, for example, has a number of allies beyond those mentioned above that are typically not considered to be under its nuclear umbrella (e.g. Egypt). And if a line is to be drawn between Japan, South Korea, and Australia on the one hand, and Thailand and the Philippines on the other, it would require more to go by than the language of the defence treaties. The wording of the Mutual Defence Treaty between the United States and the Philippines, for instance, is almost identical to that of the United States’ alliance treaties with Japan, South Korea, and Australia. A treaty-based alliance involving a nuclear-armed state, then, does not seem to be a sufficient condition for the existence of a nuclear umbrella. Whether it is a necessary condition is less clear, but for most of the cases reviewed in this paper, it does in practice seem to be the basis for the arrangements.

A second question regarding the status of nuclear umbrellas relates to whether the arrangements need to be formalized in a joint policy document, with the Strategic Concept of NATO as the main example. If so, that would exclude the case of Australia, where the arrangement has not been formalized in writing. In fact, ‘there is no known United States official statement specifically providing an assurance of American nuclear protection for Australia’.[xxxii] Instead, the basis for categorizing Australia as a nuclear umbrella state stems from Australia’s own declaration of its existence, coupled with the general US nuclear posture. This ‘double confirmation’ suggests that the lack of a formal policy does not, therefore, preclude the existence of a nuclear umbrella. The reaction by the United States to New Zealand’s opposition to port visits by nuclear-armed ships underscores this point—US officials were clearly of the view that ANZUS constituted a ‘nuclear alliance’.

On this basis we may distinguish between nuclear umbrellas explicitly articulated in official political documents (‘formalized’ nuclear umbrellas), and nuclear umbrellas based only on implicit understandings or acquiescence (‘non-formalized’ nuclear umbrellas). But where does that bring us in terms of categorizing the CSTO? On the one hand, the Russian Secretary General of the CSTO has declared that a Russian nuclear umbrella exists over the members of that organization. On the other hand, the same claim has not been made by Russia itself. Nor does it seem to have been made by any of the other member organizations. Add to this the fact that three of the CSTO members are part of a nuclear-weapon-free zone, a treaty that all the NPT nuclear-weapon states have now agreed to uphold, and it becomes difficult to categorically decide whether or not the CSTO constitutes a nuclear umbrella. In such cases, where no official declaration confirming the existence of a nuclear umbrella has been made by either of the states involved, our assumption would be that unless all ‘parties’ in a potential umbrella arrangement explicitly recognizes it as such, it should not be seen as a nuclear umbrella.

If we conclude, however, that the CSTO should not be considered a nuclear umbrella, this does not exclude the possibility that one or more of the CSTO-members could be in a bilateral nuclear security alliance with Russia. Since the three Central-Asian members of the alliance are part of a nuclear-weapon-free zone, the most likely cases would be Belarus and Armenia. With regards to Armenia, there has been some hinting from different actors in recent years that the country is indeed protected by Russian nuclear weapons. In an interview with Russian newspaper Pravda in 2012, Vice President of the Moscow-based Academy of Geopolitical Issues, Konstantin Sivkov, stated that ‘Armenia is fully protected with the Russian umbrella of both conventional forces as well as strategic nuclear forces’.[xxxiii] Yet, as in the case of CSTO above, the same message does not appear to have been communicated from official Armenian sources, nor from their Russian counterparts (except through the general Russian nuclear doctrine).

For Belarus, the situation is different. President Alexander Lukashenko has stated, on several occasions, that the Russian nuclear umbrella also extends to Belarus. In 2011, for instance, he is reported to have said that Belarus is ‘now under the protection of Russia’s nuclear umbrella.’[xxxiv] This has not, to our knowledge, been denied by the Kremlin, and with Russia’s blanket extension of nuclear security guarantees to all its allies (much like the United States), this leaves Belarus in a similar category as Australia (except from the fact that Belarus is not part of a nuclear-weapon-free zone).

How, then, should we define a nuclear umbrella? Based on the discussion above, we would propose to conclude that a nuclear umbrella exists when both of the following elements hold true:

  • A nuclear-armed state is required to guarantee the security of a non-nuclear-armed state;
  • Both the extender and the receiver of this security guarantee has officially declared, jointly or separately, that nuclear weapons could be used in order to fulfil this obligation.

A ‘nuclear umbrella’ can thus be defined as an international security arrangement under which the participating states have made clear that nuclear weapons could be used in their defence. The related concept of ‘extended nuclear deterrence’ may be understood as the intended effect of a nuclear umbrella. A ‘nuclear umbrella state’ is consequently a state without nuclear weapons under the supposed protection of the nuclear weapons of another state.

This definition of a nuclear umbrella would include NATO, Japan, Australia, and South Korea, but not Thailand, the Philippines or Taiwan, nor the whole of the CSTO. The only CSTO member that would constitute a nuclear umbrella state according to this definition is Belarus.


The term nuclear umbrella is in frequent use in multilateral disarmament discussions, yet despite the apparent straightforwardness with which it is used, the term lacks a clear definition that can help determine the borderline cases. Based on a review of the military alliances commonly referred to as nuclear umbrellas, we propose that a definition should require both the extender and the receiver of the nuclear security guarantee to explicitly express the existence of a nuclear option in their joint defence doctrine. Whether this is done in written documents or through declarations is of less importance, as long as it is made by official government sources. This brings us to conclude that beyond NATO, only four states should be counted as nuclear umbrella states: Australia, Japan, South Korea, and Belarus.

Finally, it should be reiterated that nuclear umbrellas are not legal concepts. In fact, although the nuclear umbrellas are all predicated on legally binding security treaties, nuclear weapons are not mentioned in any of them. Rather than being legal concepts, nuclear umbrellas should be understood as political constructs.


[i]     Including by itself, see NATO, ‘Active Engagement, Modern Defence’, adopted 20 November 2010, para. 17.

[ii]     NATO, ‘Overall Strategic Concept for the Defense of the North Atlantic Treaty Organization Area’ (MC 14/2), 23 May 1957, para. 13(c).

[iii]     http://www.nato.int/cps/en/natolive/topics_56626.htm.

[iv]     See Stein-Ivar L. Eide, ‘A ban on nuclear weapons: what’s in it for NATO?’, ILPI Policy Paper, no. 5/2014, http://nwp.ilpi.org/wp-content/uploads/2015/03/PP05-14-NATO-and-a-BAN.pdf.

[v]     Active Engagement, Modern Defence: Strategic Concept for the Defence and Security of the Members of the North Atlantic Treaty Organization Adopted by Heads of State and Government at the NATO Summit in Lisbon 19-20 November 2010, para. 17.

[vi]     Ibid., para. 27.

[vii]     Treaty on the Non-Proliferation of Nuclear Weapons, Art. VI.

[viii]    See Steve Andreasen et. al (2016) ‘Post-Warsaw analysis: What NATO said (or didn’t say) about Nuclear Weapons’, Nuclear Threat Initiative: http://www.nti.org/analysis/articles/post-warsaw-analysis-what-nato-said-or-didnt-say-about-nuclear-weapons/.

[ix]     Security Treaty Between the United States and Australia and New Zealand, adopted 1 September 1951, Article IV. http://avalon.law.yale.edu/20th_century/usmu002.asp. Similar wording can be found in the security treaties between the United States and Japan, the Philippines, and South Korea.

[x]     See Michael Hamel-Green, ‘Nuclear Umbrella or Nuclear Free? Australia’s Disarmament Dilemma’, ILPI Background paper no 8/2014, http://nwp.ilpi.org/?p=2479.

[xi]     Ministry of Defence talking points on ’Australian Government’s Stance on Nuclear Weaponry’, available at http://www.defence.gov.au/foi/docs/disclosures/421_1213_Documents.pdf (last accessed 31/05/16).

[xii]     US Nuclear Posture Review (2010): http://www.defense.gov/Portals/1/features/defenseReviews/NPR/2010_Nuclear_Posture_Review_Report.pdf.

[xiii]    Joint Statement of the Security Consultative Committee Toward a More Robust Alliance and Greater Shared Responsibilities, 3 October 2013, http://archive.defense.gov/pubs/U.S.-Japan-Joint-Statement-of-the-Security-Consultative-Committee.pdf

[xiv]     Treaty of Mutual Cooperation and Security Between the United States of America and Japan, adopted 19 January 1960, Article VI.

[xv]     Mutual Defense Treaty Between the United States and the Republic of Korea, October 1953, see treaty text at: http://avalon.law.yale.edu/20th_century/kor001.asp

[xvi]     The White House, ‘Joint Vision for the Alliance of the United States of America and the Republic of Korea’, 16 June 2009, http://www.cfr.org/proliferation/joint-vision-alliance-united-states-america-republic-korea/p19643.

[xvii]    See for example Foreign Policy, 18 May 2015, at: http://foreignpolicy.com/2015/05/18/raindrops-keep-falling-on-my-nuclear-umbrella-us-japan-south-north-korea/.

[xviii]    Article 4 of the Collective Security Treaty, see treaty text at: http://www.odkb-csto.org/documents/detail.php?ELEMENT_ID=1897.

[xix]     Military Doctrine of the Russian Federation (2014): https://www.offiziere.ch/wp-content/uploads-001/2015/08/Russia-s-2014-Military-Doctrine.pdf.

[xx]     Quoted in ‘Russia is ready to protect CSTO allies including with application of nuclear weapons’, 2010, http://www.kazakhstan.org.sg/content/intro.php?act=news&c_id=658.

[xxi]     See ‘Russia: The Nuclear Umbrella and the CSTO’, February 25, 2010, https://www.stratfor.com/analysis/russia-nuclear-umbrella-and-csto.

[xxii]    Uzbekistan withdrew from CSTO (for the second time) in 2012, leaving Kazakhstan, Kyrgyzstan, Tajikistan from Central Asia. Turkmenistan has never been a member of the CSTO.

[xxiii]    The UK reservation specified that the UK would not be bound by its obligations unless Article 12 “prohibits those actions described in its Articles 3 and 4.” Explanatory Memorandum on the Protocol to the Treaty on a Nuclear-Weapon-Free Zone in Central Asia. See http://disarmament.un.org/treaties/t/canwfz_protocol.

[xxiv]    Available from http://www.gov.ph/2014/04/29/document-enhanced-defense-cooperation-agreement/.

[xxv]     According to declassified material, the US also stored nuclear weapons in Taiwan from 1958-1974.

[xxvi]    See Vincent Wei-cheng Wang (2008), ‘Taiwan: Conventional Deterrence, Soft Power, and the Nuclear Option‘, University of Richmond: http://scholarship.richmond.edu/cgi/viewcontent.cgi?article=1121&context=polisci-faculty-publications.

[xxvii]    See Andrew O’Neil (2013) Asia, the US and Extended Nuclear Deterrence: Atomic Umbrellas in the Twenty-First Century, Routledge, p.3.

[xxviii]    Miles Yu (2013) ‘Inside China: Ukraine gets nuclear umbrella’, Washington Times, 12 December 2013.

[xxix]    Catherine Dill and Jonathan Ray (2014) ‘That’s Not What Xi Said!’, Arms Control Wonk, 16 January 2014 (emphasis original): http://www.armscontrolwonk.com/archive/207019/a-chinese-nuclear-umbrella-for-ukraine/

[xxx]     E.g. Andrew O’Neill, op.cit.

[xxxi]    Ibid. Compare Bruno Tertrais, ‘Security Guarantees and Nuclear Non-Proliferation’, Foundation pur la Recherche Stratégique, note no. 14, 2011; Mahdi D. Nazemroaya, ‘The Next World War’, Global Research, 10 January 2011,
http://www.globalresearch.ca/the-next-world-war-the-great-game-and-the-threat-of-nuclear-war/22169 (accessed 18 May 2016).

[xxxii]    Michael Hamel-Green, ‘Nuclear Umbrella or Nuclear-Free?’, Background Paper, no. 8, International Law and Policy Institute, 2014. Emphasis added.

[xxxiii]    Pravda, ‘Russia protects Armenia from Western influence’, October 19, 2012, http://www.pravdareport.com/world/ussr/19-10-2012/122506-russia_armenia_army_base_gyumri-0/.

[xxxiv]    Pravo.by – National Legal Internet Portal of the Republic of Belarus, ’Belarus shares Russia’s concern over US missile defenses in Europe’, December 2, 2011. See also https://www.armscontrol.org/node/2900.