"Though we have acheived progress, our work is not over. That is why I support the mission of the Arms Control Association. It is, quite simply, the most effective and important organization working in the field today." 

– Larry Weiler
Former U.S.-Russian arms control negotiator
August 7, 2018
Negative Security Assurances: Revisiting the Nuclear-Weapon-Free Zone Option

By Leonard S. Spector and Aubrie Ohlde

A perennial subject of contention at review conferences of the nuclear Nonproliferation Treaty (NPT), held every five years, has been the desire of the non-nuclear-weapon states-parties to the treaty to obtain “legally binding negative security assurances” from the five nuclear-weapon states-parties: China, France, Russia, the United Kingdom, and the United States.

In the context of NPT diplomacy, negative security assurances are guarantees by the five NPT nuclear-weapon states not to use or threaten to use nuclear weapons against states that have formally renounced them. The non-nuclear-weapon states have traditionally pressed for such assurances in the form of a free-standing treaty.

Negative security assurances will surely be a controversial subject at the May 2005 NPT Review Conference in New York. Before the rhetoric obscures the reality, however, it is worth revisiting one approach for addressing this issue: the extension of binding negative security assurances by means of protocols to treaties establishing nuclear-weapon-free zones (NWFZs). To be sure, this strategy falls short of a universal approach. Yet, for the states it would cover, extending negative security assurances by means of NWFZs promotes the core value associated with a universal non-use treaty: the fundamental principle that nations that have renounced nuclear weapons should be protected from being the targets of such arms.

The NWFZ approach is also far more likely to win favor from NPT nuclear-weapon states. Currently, only China has indicated its unreserved support for broader guarantees based on a new treaty.[1] Russia supports an international agreement on the subject but “with reservations concerning cases in which nuclear weapons may be used.”[2] The other NPT nuclear-weapon states have resisted such binding, universal undertakings. The United Kingdom argues, for example, that “the way forward is to make further progress with nuclear-weapon-free zones, which will provide, on a credible, regional basis, the internationally binding legal instruments on [negative security assurances] that many are looking for.”[3]

Underlying the reluctance of these NPT nuclear-weapon states is concern that a binding, universal negative security assurances treaty might unduly constrain military options and weaken the perceived strength of commitments to defend allies in conflict-prone regions. The region-by-region extension of binding negative security assurances via NWFZs permits the NPT nuclear-weapon states to accept added restrictions more selectively, as circumstances warrant. It also provides non-nuclear-weapon states with a practical path by which they can move forward with the realization of such guarantees.

A Heated but Sterile Debate
During the past decade, the diplomatic clash over negative security assurances has heated up, with actions unfolding predominantly during the review conferences themselves, as well as in related UN fora, such as the annual preparatory sessions for these events; the Conference on Disarmament in Geneva; and the “First Committee” of the UN General Assembly, covering disarmament and international security.[4]

The dispute is also reflected in the associated unilateral political declarations containing non-use pledges that the NPT nuclear-weapon states have made with a view toward influencing the debate at these various meetings. Most notably, in 1995, in conjunction with the NPT Review and Extension Conference, the five NPT nuclear-weapon states reiterated their pre-existing unilateral negative security assurances, and the UN Security Council adopted a unanimous resolution welcoming these declarations and incorporating them.[5]

Some have argued that this action, along with the fact that the NPT non-nuclear-weapon states relied on such assurances in accepting an indefinite extension of the treaty in 1995, have made the assurances legally binding. The United States disputes this, arguing in part that the assurances are not binding “international agreements” because the assurances were not adopted domestically in accordance with the procedures mandated by the U.S. Constitution. Presumably, China and Russia also consider their existing unilateral, political negative security assurances and those of the other NPT nuclear-weapon states to be nonbinding; if the two states considered the pledges to be binding, there would be no need for a negative security assurances treaty, which the two support.

Moreover, in practice, many of the nuclear-weapon states have hedged on the scope of these guarantees. For example, the United States has said that it would not rule out using nuclear weapons against countries that attack it or its allies with biological or chemical weapons. In addition, all of these states, aside from China, reserve the right in their assurances to use nuclear weapons to respond to attacks by non-nuclear-weapon states undertaken in alliance or in association with an NPT nuclear-weapon state.[6]

In recent years, the demand for legally binding negative security assurances has been pressed most forcefully by the members of the Nonaligned Movement. Like the Western Group, the Nonaligned Movement normally advances its diplomatic agenda through bloc voting at NPT review conferences and in related fora. To be sure, a number of other non-nuclear-weapon states, such as Norway, Sweden and Ukraine, have also encouraged the extension of legally binding negative security assurances. The issue is also a tenet of the grouping of Brazil, Egypt, Ireland, New Zealand, Mexico, South Africa, and Sweden, known as the New Agenda Coalition. Yet, the Nonaligned Movement is their foremost champion.

A Better Approach
As noted earlier, however, negative security assurances have already taken hold in a second setting outside the NPT review context, namely, in “non-use” protocols to NWFZ treaties.[7] In these legally binding protocols, NPT nuclear-weapon states formally undertake, among other restrictions, not to use or threaten to use nuclear weapons against parties to the NWFZ treaties.

Non-use guarantees provided in the latter context offer NPT non-nuclear-weapon states one crucial advantage in comparison to more generalized, unilateral negative security assurances: There is no question that, if a NWFZ treaty is in force, duly ratified protocols to that treaty are legally binding vis-à-vis the zonal parties.

Certainly, even some of these guarantees are qualified. Their legal status, however, is not, thus offering the non-nuclear-weapon states a surer path toward protection than the so far futile debate over attaining binding and universal negative security assurances via a separate treaty.[8]

Indeed, if non-use protocols to current or pending African, Central Asian, Latin American, Southeast Asian, and South Pacific NWFZs were all to enter into force and these NWFZ treaties were ratified by all states in these zones, more than half of the NPT non-nuclear-weapon states would be covered by legally binding negative security assurances, including nearly four-fifths of the Nonaligned Movement.[9] Those covered would include the considerable majority of the states most vocally advocating the case for legally binding negative security assurances, including Egypt, Indonesia, Malaysia, and Nigeria. Such developments could go far to defuse the debate within the NPT over such assurances and reinforce the sense of common purpose among its parties. If, in addition to these “active” NWFZs, a Middle Eastern NWFZ were to emerge, negative security assurances would likely cover about seven-eighths of the Nonaligned Movement, further reinforcing these trends.[10]

Nor do these states have to wait until these zones fully enter into force to benefit from these protections. Once an NWFZ treaty is opened for signature and an NPT nuclear-weapon state has signed the treaty’s non-use protocol, the nuclear-weapon state is bound by international law not to act in a manner that would “defeat the object and purpose” of that instrument.[11] This principle is a part of customary international law, which extends to all states and is codified in Article 18 of the Vienna Convention on the Law of Treaties, to which China, Russia, and the United Kingdom are parties and which the United States has signed. Although application of this principle falls short of fully legally binding assurances, it does carry legal significance and creates a stronger obligation than that arising from mere unilateral political declarations.[12]

The NWFZ option has been suggested in previous NPT fora, but it has been discounted by Nonaligned Movement representatives. Sola Ogunbanwo of Nigeria, speaking at the 2000 NPT Review Conference, for example, noted the value of NWFZs as a “further step in the direction of a nuclear-weapon-free world” but then went on to state, “The fact that 110 United Nations member states already have security assurances through memberships in NWFZ treaties should not prevent the negotiation and conclusion of a legally binding treaty on security assurances for NPT parties.”[13] Nigeria has demonstrated its commitment to NWFZs by ratifying the Treaty of Pelindaba and is thus very close to obtaining legally binding non-use assurances by this means.[14] Because a universal treaty would be redundant for states covered by NFWZ non-use protocols, Ogunbanwo’s stance is likely motivated by the desire to extend such protections to the additional NPT non-nuclear-weapon states not currently included in NFWZs.

Potential Coverage Offered by NWFZs
Currently, three NWFZs are in force in Latin America and the Caribbean; the South Pacific; and Southeast Asia. Another zone in Africa has not yet received sufficient ratifications to enter into force. Nevertheless, many states within these zones already benefit, to a greater or lesser extent, from the non-use pledges contained in the protocols to the respective NWFZ treaties.

To date, there is only one zone, Latin America and the Caribbean, in which all of the NPT nuclear-weapon states have ratified the non-use protocols.

In the South Pacific, all of the NPT nuclear-weapon states have ratified the non-use protocol, except for the United States. The United States signed the agreement March 26, 1996, but the Clinton administration did not submit the instrument to the Senate for its advice and consent to ratification; the Bush administration has also not taken this step. Still, the United States would appear to be bound to uphold the purpose of this treaty under customary international law, as reinforced by the U.S. signing of the Vienna Convention.

By contrast, none of the NPT nuclear-weapon states has signed or ratified the non-use protocol to the Southeast Asian NWFZ, principally because of concerns over the broad definition of the zone and the potential impact this might have on such issues as freedom of navigation.[15] Although China announced in April 2004 that it had “reached agreement” with the members of this NWFZ on the treaty and its protocol, it has not yet signed or ratified the latter.[16]

In particular, NPT nuclear-weapon states have been concerned that the broad definition of the zone would set a precedent of potentially restricting the transit of nuclear weapons by them through certain areas.[17] They are also worried that the non-use protections of the protocol might extend to other, nonzonal states that might be operating in those ocean areas. (China has a no-first-use policy that it applies universally and is, therefore, less concerned about this issue.) Negotiations between the zonal states and the NPT nuclear-weapon states have been undertaken to seek a compromise on these issues, but they have not yet resolved the matter.

In the case of the African NWFZ, which is not yet in force, all of the nuclear-weapon states have signed the non-use protocol, but only China, France, and the United Kingdom have ratified it. Still, Russia and the United States are not known to have any substantive objection to doing so. It is possible that they are awaiting the entry into force of the Treaty of Pelindaba, which still requires ratification by nine additional zonal states, before engaging their domestic political processes to meet the procedural requirements for ratification of the non-use protocol. Nonetheless, even before entry into force, the zone would seem to provide some legal protection for many of the non-nuclear-weapon states within it. The strength of this obligation may be greatest between zonal states that have ratified the treaty and the NPT nuclear-weapon states that have similarly ratified the non-use protocol. Yet, the obligation would appear to extend in some measure from all protocol ratifiers and signatories even to zonal states that have signed but not yet ratified the treaty because the use or threatened use of nuclear weapons against such zonal states would defeat the object and purpose of the protocol vis-à-vis these anticipatory parties.

Can the Nonaligned Movement Move Forward?
The Nonaligned Movement claims 115 member states at the present time. Several of these are not parties to the NPT: India, Pakistan, and North Korea.[18] This leaves 112 nations that might claim the benefit of negative security assurances in return for their relinquishment of nuclear weapons under the NPT. Of these, more than 79 percent (all but 23 countries) are within the five current or planned NWFZs and, therefore, have the potential to obtain legally binding negative security assurances under the various NWFZ treaties.[19] Of course, some critical areas, most notably the Middle East and South Asia, are not covered by these treaties. Clearly, however, on the whole, members of the Nonaligned Movement may themselves hold the key to rapidly obtaining legally binding negative security assurances for the vast majority of their members. The necessary steps appear to be relatively straightforward. First, nine additional states must ratify the Treaty of Pelindaba (34 African states have yet to do so) to bring the African NWFZ into force and make binding the ratifications of its non-use protocol by China, France, and the United Kingdom. There appear to be no substantive barriers to subsequent Russian and U.S. ratifications, although there appears to be general reluctance on the part of the Bush administration to accept new restrictions on the use of U.S. military capabilities. Once the remaining NPT nuclear-weapon states have ratified the protocol, additional zonal states that ratified the treaty (beyond the required 28) would also receive legally binding negative security assurances from all NPT nuclear-weapon states.

The African NWFZ treaty places few, if any, new burdens on the regional states, as they are already bound to forgo nuclear weapons as parties to the NPT. It would, however, offer legally binding non-use assurances, among other advantages. In these circumstances, the failure of the regional states to bring the Treaty of Pelindaba into force raises questions as to the importance of the treaty’s presumed benefits to these parties. Indeed, their inability to move the treaty forward could well be cited by the NPT nuclear-weapon states at the upcoming review conference as evidence that their demands for binding negative security assurances lack urgency and sincerity.

Similarly, in the South Pacific, three NAM members—Marshall Islands, Micronesia, and Palau—need to ratify the Treaty of Rarotonga in order to benefit from the existing negative security assurances given by four of the five NPT nuclear-weapon states. Like their African counterparts, their failure to take this step undercuts the credibility of their demands for a free-standing negative security assurances treaty.

In Southeast Asia, the matter is more complex because there appear to be substantive differences between the zonal states and the nuclear powers. In this setting, however, the regional players must determine which is more important to them: promoting their sovereignty goals vis-à-vis the ocean areas in dispute or obtaining legally binding negative security assurances. If they determine that standing by principle in the former arena is their greater objective, then an impasse may continue, but it would be difficult for them to place blame on the NPT nuclear-weapon states as being unwilling to offer them the desired legally binding assurances.[20]

For their part, individual NPT nuclear-weapon states that have signed but not yet ratified non-use protocols to particular NWFZ treaties could demonstrate their commitment to the NWFZ approach for achieving legally binding non-use assurances by promptly concluding these ratifications. Specific steps by the United States to advance the ratification of the non-use protocol to the South Pacific NWFZ and by Russia and the United States to move toward ratification of the non-use protocol to the African NWFZ would certainly be welcome demonstrations of good faith.

Additional Considerations
To be sure, the NWFZ approach will not address every reason that non-nuclear-weapon states have articulated for seeking a treaty on binding negative security assurances. The unilateral, political negative security assurances given by four NPT nuclear-weapon states (all but China) contain a significant exception intended to permit the use of nuclear weapons to respond to attacks by non-nuclear-weapon states undertaken in alliance or in association with an NPT nuclear-weapon state.[21] The United States, in ratifying the non-use Protocol to the Treaty of Tlatelolco, has included an “understanding” that attempts to preserve this exception in that setting, and it may well do the same in ratifying other similar protocols. Because few members of the Nonaligned Movement in the NWFZs have military alliances with NPT nuclear-weapon states, however, this exception will have no practical impact in the vast majority of cases.[22]

In addition, the United States has stated, both in the context of its signature of the non-use protocol to the African NWFZ and in other settings, that it will not rule out the use of any weapon in its arsenal in response to the use against the United States of any weapon of mass destruction, citing the doctrine of belligerent reprisal.[23] Because the vast majority of non-nuclear-weapon states that belong to these zones are parties in good standing to the Chemical Weapons Convention and the Biological Weapons Convention,[24] which prohibit possession of such weapons, the practical impact of this qualification to U.S. negative security assurances will again be minimal. It is also difficult to imagine any state that is a party to these conventions openly objecting to this exception because to do so would be to reveal publicly the state’s intention to abrogate these treaties at some future time. Moreover, with the possible exceptions of Egypt, Sudan, and Myanmar, which have sometimes been alleged to possess chemical or biological weapons, no states within the active NWFZs have been identified as possessing chemical or biological arms, again minimizing the impact of this qualification.[25]

Third, the non-use protocols to the various NWFZs do not protect zonal members against the use of nuclear weapons by India, Israel, North Korea, or Pakistan because these states, known or believed to possess nuclear weapons, are not considered nuclear-weapon states within the definition established by the NPT,[26] and only such NPT states have been invited to sign the NWFZ non-use protocols.[27] The non-NPT nuclear-weapon states are surely a matter of great concern for many members of the Nonaligned Movement and of the international community more broadly. As a rule, however, concerned states have not focused on obtaining negative security assurances from the non-NPT nuclear powers, but rather on gaining their agreement to renounce nuclear arms. This has been a particular point of principle for Egypt, which has linked its ratification of the African NWFZ to the establishment of a Middle Eastern NWFZ that includes Israel as a denuclearized party. Yet, even if Egypt adheres to this stance and declines to ratify the Treaty of Pelindaba, it would still be possible for all other African states to obtain legally binding negative security assurances from the NPT nuclear-weapon states by joining this accord.

In the end, exploiting NWFZs to obtain binding negative security assurances for NPT non-nuclear-weapon states can be only a partial remedy to the demands for legally binding negative security assurances. Nonetheless, because so many of the states that have expressed deep concern over this issue are found within such zones, it seems worthwhile to take advantage of this option, which is embedded in all of the NWFZ treaties and, indeed, represents one of the most important benefits of such treaties for zonal states. Perhaps most importantly, the NPT nuclear-weapon states appear to have fewer political qualms about such agreements, offering a practical path to granting a significantly greater measure of protection to the zonal states in most cases. In some instances, such as in Southeast Asia, difficult political choices may be required to expand coverage of NWFZ non-use protocols. In many other cases, however, particularly in Africa and the South Pacific, only modest political investment would be needed to extend legally binding assurances to a far wider group of states than currently enjoy them.


1. See Hu Xiaodi, Statement at the Third Session of the Preparatory Commission (PrepCom) for the 2005 nuclear Nonproliferation Treaty (NPT) Review Conference, April 26, 2004 (hereinafter Xiaodi statement).

2. “Statement of the Delegation of the Russian Federation at the Third Session of the Preparatory Committee for the 2005 NPT Review Conference, on Negative Security Assurances for Non-Nuclear Weapon States and Establishment of Nuclear-Weapon-Free Zones,” May 3, 2004, p. 2.

3. David Broucher, “Cluster I: Specific Time: Disarmament/NSAs,” May 3, 2004 (statement at the 2004 NPT PrepCom).

4. See Hussein Haniff, Statement on behalf of the Non-Aligned Movement during Cluster I discussion of the 2004 Prepcom, April 30, 2004; 2004 NPT Review Conference PrepCom working paper on security assurances submitted by China, NPT/CONF.2005/PC.III/WP.9; “Security Assurances,” 2003 PrepCom working paper, NPT/CONF.2005/PC.II/WP.11 (submitted by New Zealand on behalf of members of the New Agenda Coalition [NAC]); 2000 Review Conference working paper on security assurances submitted by Egypt, NPT/CONF.2000/MC.I/WP.1; “Conclusion of Effective International Arrangements to Assure Non-Nuclear-Weapon States Against the Use or Threat of Use of Nuclear Weapons,” UN First Committee draft resolution, A/C.1/57/L.40, October 10, 2002, available at http://www.reachingcriticalwill.org (proposed by Bangladesh, Brunei Darussalam, Colombia, Cuba, Democratic People’s Republic of Korea, Egypt, Fiji, Indonesia, Iran, Jordan, Malaysia, Myanmar, Pakistan, Sri Lanka, Sudan, Vietnam, and Zambia).

5. See UN Security Council Resolution 984 (1995).

6. See Joseph F. Pilat, “Reassessing Security Assurances in a Unipolar World,” Washington Quarterly 28, no. 2 (Spring 2005), pp. 159-170; “Interview with John Bolton,” Arms Control Today, March 2002, pp. 3-8.

7. These are Protocol II to the Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (Treaty of Tlatelolco); Protocol II to the South Pacific Nuclear-Free-Zone Treaty (SPNFZ Treaty, Treaty of Rarotonga); Protocol I to the Southeast Asian Nuclear-Weapon-Free-Zone Treaty (SEANWFZ, Treaty of Bangkok); and Protocol II to the African Nuclear-Weapon-Free-Zone Treaty (Treaty of Pelindaba), not yet entered into force. In the current draft of the treaty to create the Central Asian Nuclear-Weapon-Free Zone, the subject is thought to be covered in Protocol I.

8. See George Bunn, “The Legal Status of U.S. Negative Security Assurances to Non-Nuclear Weapon States,” Nonproliferation Review 4, no. 3 (Spring-Summer 1997), p. 1; George Bunn and Roland Timerbaev, “Security Assurances to Non-Nuclear-Weapon States: Possible Options for Change,” PPNN Issue Review, no. 7 (September 1996), p. 1.

9. In the case of the Central Asian NWFZ, on February 7-9, 2005, the Regional Group of Experts (from Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan, and the United Nations) negotiating the treaty establishing the zone met in Tashkent and agreed on the draft of the treaty. The signing date is to be announced. “Text of the Treaty Establishing a Nuclear-Weapon-Free Zone in Central Asia Agreed in Tashkent” Itar-Tass, February 9, 2005.

10. The yet-to-be-defined Middle East NWFZ cannot be considered “active” at this time, and the well-known opposition of Israel makes early entry into force of such a zone unlikely. Egypt has conditioned its ratification of the African NWFZ on the advent of a Middle Eastern NWFZ under which Israel would give up its nuclear capabilities.

11. Vienna Convention of the Law of Treaties, Article 18. It was completed in Vienna on May 23, 1969, and entered into force on January 27, 1980.

12. The term “legal significance” was suggested to the authors by Carlton Stoiber.

13. The statement that 110 states “already have” binding negative security assurances by virtue of NWFZs exaggerates the situation considerably. A better choice of words would have been that 110 states have the “opportunity to obtain” such assurances by means of these zones.

14. Although this particular statement by a Nonaligned Movement state discounts the worth of negative security assurance provided via the NWFZs, Paragraph 80 of the roughly contemporaneous Official Document of the XIII Summit of the Nonaligned Movement (April 9, 2000) appears indirectly to support this approach. It notes that, “in the context of nuclear-weapon-free zones, it is essential that nuclear-weapon states should provide unconditional assurances against the use or threat of use of nuclear weapons to all states of the zone.”

15. See Thomas Graham, “Why U.S. Has Not Signed Protocol to Nuclear Arms Treaty,” New Straits Times, June 24, 1997.

16. See Xiaodi statement.

17. The currently proposed definition of the zone includes exclusive economic zones and continental shelf areas, which all NPT nuclear-weapon states agree are not subject to national sovereignty.

18. Palestine, which is not yet a state, also belongs to the Nonaligned Movement.

19. If the 16 observers to the Nonaligned Movement are included, the total number of Nonaligned Movement members and observers eligible for negative security assurances is 127. Of these, 99 states are potential recipients of binding negative security assurances via the “active” NWFZs. In addition, whether Timor Leste is covered by negative security assurances is somewhat uncertain. It is geographically within the Southeast Asian NWFZ, but is not a party to the Treaty of Bangkok.

20. As noted, the states not currently covered by NFWZs are primarily in the Middle East, South Asia, and Europe. Like a Middle Eastern NFWZ, a South Asian NFWZ seems at best a distant hope, given the unfolding nuclear arms race between India and Pakistan. In Europe, where managing the expansion of the European Union and NATO are front-burner geopolitical concerns, there seems to be little interest in developing a new regional pact focused on nuclear disarmament.

21. The U.S. version, most recently restated by Department of State spokesperson Richard Boucher on February 22, 2002, states that “[t]he United States reaffirms that it will not use nuclear weapons against non-nuclear-weapon state-parties to the Treaty on the Nonproliferation of Nuclear Weapons, except in the case of an invasion or any other attack on the United States, its territories, its armed forces or other troops, its allies, or on a state toward which it has a security commitment carried out, or sustained by such a non-nuclear-weapon state in association or alliance with a nuclear-weapon state.” At the third session of the PrepCom for the 2005 NPT Review Conference, the United States reaffirmed that there has been no change in these U.S. assurances. Stephen G. Rademaker, Statement at the Third Meeting of the PrepCom for the 2005 NPT Review Conference, May 3, 2004.

22. Members of the Nonaligned Movement are by definition presumably not allied to any major power. Nonetheless, conceivably Cuba, by virtue of its long-standing ties to Russia, might be deemed to have alliance-like links to an NPT nuclear-weapon state. It is difficult to imagine Cuba engaging in military action against French, British, or U.S. forces or allies that might lead to a nuclear response. Thus, the impact of the exception vis-à-vis Nonaligned Movement states in NWFZs is largely a moot question. The exception was initially designed to address possible aggression by NPT non-nuclear-weapon states that were members of the Warsaw Pact and by North Korea prior to the time it acquired nuclear arms.

23. In his February 22, 2002, statement, for example, Boucher addressed this issue, saying, “Furthermore, the policy [regarding the use of nuclear weapons against non-nuclear-weapon state-parties to the NPT] says that we will do whatever is necessary to deter the use of weapons of mass destruction against the United States, its allies, and its interests. If a weapon of mass destruction is used against the United States or its allies, we will not rule out any specific type of military response.”

24. Of the 112 relevant members of the Nonaligned Movement, 89 are parties to the Chemical Weapons Convention and 85 are parties to the Biological and Toxin Weapons Convention.

25. On this issue, see James A. Russell and James J. Wirtz, “Negative Security Assurances and the Nuclear Posture Review,” Strategic Insights (July 2002).

26. The NPT defines a “Nuclear Weapon State” as a state that had detonated a nuclear explosion prior to January 1, 1967.

27. See Article 4 of the Treaty of Pelindaba, which states, “This Protocol shall be open for signature by China, France, the Russian Federation, the United Kingdom of Great Britain and Northern Ireland, and the United States of America.” Whether the NWFZ treaties should be amended to permit adherence to their non-use protocols by the four non-NPT nuclear-weapon states or whether the four might adhere to the protocols unilaterally is beyond the scope of this article.

Leonard S. Spector is deputy director of the Center for Nonproliferation Studies at the Monterey Institute of International Studies and leads the center’s Washington, DC, office. Aubrie Ohlde is a research associate at the center.