Nobel Lecture, December 11, 1982

The Latin American Nuclear-Weapon Free Zone

In seems advisable to point out from the outset that the Latin American nuclear-weapon-free zone has the privilege of being the only one in existence which covers densely inhabited territories. Outside it only in Antarctica, the Outer Space and the sea bed are similar prohibitions in force, based on treaties concluded in 1959, 1967 and 1971, respectively.

The official title of the treaty which established the Latin American zone and defined its statute is the “Treaty for the Prohibition of Nuclear Weapons in Latin America”, but it is usually referred to as the “Treaty of Tlatelolco”, employing the Aztec name for the district of the Mexican capital where the Ministry of Foreign Affairs of Mexico is located and where the treaty itself was opened to signature almost sixteen years ago, on February 14, 1967.

The modest purpose of this lecture is to provide a synoptic view both of the genesis and the provisions of the treaty.

I. Genesis of the Treaty of Tlatelolco

The first international document in the history of the events directly related to the genesis of the Treaty of Tlatelolco was the Joint Declaration of 29 April 1963. In this declaration the Presidents of Bolivia, Brazil, Chile, Ecuador and Mexico announced that their governments were willing to sign a Latin American multilateral agreement by which they would undertake not “to manufacture, store, or test nuclear weapons or devices for launching nuclear weapons”.

Seven months later, the United Nations General Assembly, taking as a basis a draft resolution submitted by eleven Latin American countries (the five previously mentioned, plus Costa Rica, El Salvador, Haiti, Honduras, Panama and Uruguay), approved on 27 November 1963 resolution 1911 (XVIII). In this resolution inter alia the General Assembly welcomed the initiative of the five Presidents for the military denuclearization of Latin America; expressed the hope that the States of the region would initiate studies “concerning the measures that should be agreed upon with a view to achieving the aims” of the Joint Declaration, and requested the Secretary-General of the United Nations to extend to the States of Latin America, at their request, “such technical facilities as they may require in order to achieve the aims set forth in the present resolution”.

Almost one year elapsed between the adoption of this General Assembly resolution and the next step worth mentioning in a review of the antecedents of the treaty. This interval was not wasted, however. The Mexican Government put it to good use with active diplomatic consultations which resulted in the convening of a Latin American conference known as the “Preliminary Session on the Denuclearization of Latin America” (or REUPRAL, its Spanish acronym). Meeting in Mexico City from 23 to 27 November 1964, REUPRAL adopted a measure which was later to prove decisive for the success of the Latin American enterprise – the creation of an ad hoc organ, the “Preparatory Commission for the Denuclearization of Latin America” (known also by its Spanish acronym, COPREDAL). The Preparatory Commission was specifically instructed (in the same resolution whereby it was established) “to prepare a preliminary draft of a multilateral treaty for the denuclearization of Latin America, and to this end, to conduct any prior studies and take any prior steps that it deems necessary”.^*

COPREDAL had its first session in Mexico City from 15 to 22 March 1965. In this session, the Commission adopted its rules of procedure and set up four subsidiary organs: a Coordination Committee and three working groups. Subsequently the Commission would create another subsidiary organ – the “Negotiating Committee”.

The Preparatory Commission held a total of four sessions, the last of which took place just under two years after its creation, from 31 January to 14 February 1967. Contrary to what has generally happened with other disarmament treaties and conventions, the draft articles for the future treaty dealing with verification, inspection, and control were the first to be completed at the second session of the Commission (23 August-2 September 1965). At that time a full declaration of principles was also drafted to serve as a basis for the Preamble of the draft treaty.

During its third session, COPREDAL received from its Coordinating Committee a working paper which contained the complete text of a preliminary draft for the treaty that the Commission had received the mandate to prepare. This draft, together with other proposals submitted by member states, provided the basis for the deliberations of the session. Their result was the unanimous approval of a document entitled “Proposals for the Preparation of the Treaty for the Denuclearization of Latin America” which played as prominent a role in the history of the treaty as that of the Dumbarton Oaks proposals in the history of the United Nations¹ These “Proposals” included all provisions which might prove necessary for the treaty as a whole, although in some cases COPREDAL, not having been able to find solutions satisfactory to all, had been obliged to present to the Governments two parallel alternatives.

From those few pending questions which the Commission would be called upon to solve at its fourth session, the most important one was the entry into force of the treaty. This issue provoked what was probably the greatest discussion in COPREDAL’s proceedings. Because of this problem and due to the positive precedent established by COPREDAL’s solution to the problem, it is worth examining the proceedings in somewhat greater detail.

When the Preparatory Commission considered this subject in April 1966, two distinct views became apparent. According to the first view, the treaty should come into force, between states which would ratify it, on the date of deposit of their respective instruments of ratification, in keeping with standard practice. The representative Latin American body to be established by the treaty should begin to function as soon as eleven instruments of ratification were deposited, as this number constituted a majority of the twenty-one members of the Preparatory Commission. Those states supporting the alternative view argued that the treaty, although signed and ratified by all member states of the Preparatory Commission, should enter into force only upon completion of four requirements, essentially those defined in Article 28 of the treaty. These four requirements may be summarized as follows: the signature and ratification of the Treaty of Tlatelolco and its Additional Protocols I and II by all states to which they were opened, and the conclusion of bilateral or multilateral agreements concerning the application of the Safeguards System of the International Atomic Energy Agency by each party to the treaty.

As a result of these differing views COPREDAL was obliged to present, in its proposals, two parallel texts. These texts stated respectively the provisions that the treaty would contain, according to whether one accepted the first or the second thesis. To solve the problem, the Coordinating Committee, in its report of 28 December 1966, suggested the adoption of a conciliatory formula, which could receive the approval of all member states of the Commission without detriment to their respective positions on the alternative texts. It was this formula, with some modifications, which was finally adopted and incorporated into Article 28 of the treaty. In keeping with it, the treaty would go into effect for all states that had ratified it upon completion of the four requirements specified in paragraph 1 of Article 28. That notwithstanding, the second paragraph of the Article states:

“All signatory states shall have the imprescriptible right to waive, wholly or in part, the requirements laid down in the preceding paragraph. They may do so by means of a declaration which shall be annexed to their respective instrument of ratification and which may be formulated at the time of deposit of the instrument or subsequently. For those states which exercise this right, this Treaty shall enter into force upon deposit of the declaration, or as soon as those requirements have been met which have not been expressly waived”.

Moreover, the third paragraph of the same Article stipulates:

“As soon as this Treaty has entered into force in accordance with the provisions of paragraph 2 for eleven states, the Depositary Government shall convene a preliminary meeting of those states in order that the Agency may be set up and commence its work”.

As one can see, an eclectic system was adopted, which, while respecting the viewpoints of all signatory states, prevented nonetheless any particular state from precluding the enactment of the treaty for those which would voluntarily wish to accept the statute of military denuclearization defined therein.

The Treaty of Tlatelolco has thus contributed effectively to dispel the myth that for the establishment of a nuclear-weapon-free zone it would be an essential requirement that all states of the region concerned should become, from the very outset, parties to the treaty establishing the zone. The system adopted in the Latin American instrument proves that, although no state can obligate another to join such a zone, neither can one prevent others wishing to do so from adhering to a regime of total absence of nuclear weapons within their own territories.

Once the question of the entry into force of the treaty had been settled, at the fourth session of COPREDAL, the Preparatory Commission proceeded to settle, without major difficulties, the few other pending problems. On 12 February 1967, the Treaty for the Prohibition of Nuclear Weapons in Latin America was unanimously approved and two days later, at the solemn closing ceremony of the Commission’s proceedings, it was opened to signature and subscribed to by the representatives of fourteen of its twenty-one members. As of August 1982, fifteen years later, the number of signatory states stands at twenty-five, of which twenty-two are already parties to the treaty.

Additional Protocol I which is open to the four States – United Kingdom, Netherlands, United States, and France – which are internationally responsible for territories lying within the limits of the geographical zone established in the treaty, has been signed by all those states and ratified by the United Kingdom, the Netherlands and the United States. With regard to France it seems that the ratification process is at present well advanced. The five nuclear weapon states – the United Kingdom, the United States, France, China and the Soviet Union – are already parties to Additional Protocol II which is destined for them.

As provided for in paragraph 3 of Article 28 previously quoted, as soon as the treaty entered into force for eleven states, the Depositary Government convened a “preliminary meeting” of those states in order to set up the Agency for the Prohibition of Nuclear Weapons in Latin America known by its Spanish acronym OPANAL. This preliminary meeting (REOPANAL) took place in late June 1969 and carried out successfully all the preparatory work necessary for the first session of the General Conference of OPANAL. The latter was inaugurated on 2 September 1969 in the presence of U Thant, the then Secretary-General of the United Nations, and Sigvard Eklund, the Director-General of the International Atomic Energy Agency (IAEA). After seven working days the General Conference gave its approval to a series of basic juridical and administrative documents which provided the foundations for the Latin American Agency created by the treaty. To date the General Conference has held seven regular sessions and two special sessions in accordance with the provisions of Article 9.

II. Analytical Summary of the Treaty of Tlatelolco

As a complement to the above brief survey of the preparatory work leading to the conclusion of the Tlatelolco Treaty, the following paragraphs are intended to give a general idea of its contents and to carry out a brief analytical summary of some of its main provisions.

The treaty comprises a preamble, thirty-one articles, one transitional article and two additional protocols.

The preamble defines the fundamental aims pursued by the states which drafted the treaty by stating their conviction that:

“The military denuclearization of Latin America – being understood to mean the undertaking entered into internationally in this Treaty to keep their territories forever free from nuclear weapons – will constitute a measure which will spare their peoples from the squandering of their limited resources on nuclear armaments and will protect them against possible nuclear attacks on their territories, and will also constitute a significant contribution towards preventing the proliferation of nuclear weapons and a powerful factor for general and complete disarmament”.

It is also worth noting that the Final Document approved by the first special session of the UN General Assembly devoted to disarmament, which met May-June 1978, contains several declaratory statements of a striking similarity to those included in the sixteen-year-old preamble of the Treaty of Tlatelolco. The Latin American states, for instance, declared themselves convinced:

“That the incalculable destructive power of nuclear weapons has made it imperative that the legal prohibition of war should be strictly observed in practice if the survival of civilization and of mankind itself is to be assured,

That nuclear weapons, whose terrible effects are suffered, indiscriminately and inexorably, by military forces and civilian population alike, constitute, through the persistence of the radioactivity they release, an attack on the integrity of the human species and ultimately may even render the whole earth uninhabitable”.

The United Nations, for its part, has proclaimed:

“Mankind today is confronted with an unprecedented threat of self-extinction arising from the massive and competitive accumulation of the most destructive weapons ever produced. Existing arsenals of nuclear weapons alone are more than sufficient to destroy all life on earth …

Unless its avenues are closed, the continued arms race means a growing threat to international peace and security and even to the very survival of mankind …

Removing the threat of a world war – a nuclear war – is the most acute and urgent task of the present day. Mankind is confronted with a choice: we must halt the arms race and proceed to disarmament or face annihilation”.

As to the articles of the treaty, their contents may be described briefly as follows:

Article 1 defines the obligations of the parties. The following four articles (2-5) provide definitions of some terms employed in the treaty: contracting parties, territory, zone of application and nuclear weapons. Article 6 deals with the “meeting of signatories”, while Articles 7-11 establish the structure and procedures of the “Agency for the Prohibition of Nuclear Weapons in Latin America” (OPANAL) created by the treaty, and state the functions and powers of its principal organs: the General Conference, the Council and the Secretariat. The five succeeding articles (12-16) and paragraphs 2 and 3 of Article 18 describe the functioning of the “control system”, also established by the treaty. Article 17 contains general provisions on the peaceful use of nuclear energy and Article 18 deals with peaceful nuclear explosions.

Article 19 examines the relations of OPANAL with other international organizations, whereas Article 20 outlines the measures that the General Conference shall take in cases of serious violations of the treaty, such measures mainly involving simultaneous transmission of reports to the Security Council and the General Assembly of the United Nations. Article 21 safeguards the rights and obligations of the parties under the Charter of the United Nations and, in the case of states members of the Organization of American States, under existing regional treaties. Article 23 makes it binding for the contracting parties to notify the Secretariat of OPANAL of any international agreement concluded by any of them on matters with which the treaty is concerned.

The settlement of controversies concerning the interpretation or application of the treaty is covered by Article 24. Articles 22, 25-27 and 29-31 contain what is generally known as “final clauses” dealing with questions such as privileges and immunities, signature, ratification and deposit, reservations (which the treaty does not admit), amendments, duration and denunciation, and authentic texts and registration. The transitional article specifies that “denunciation of the declaration referred to in Article 28, paragraph 2, shall be subject to the same procedures as the denunciation” of the treaty, except that it will take effect on the date of delivery of the respective notification and not three months later as provided in Article 30, paragraph 2, for denunciation of the treaty. In paragraph 2 of Article 26, the Government of Mexico is designated the “Depositary Government” of the treaty whereas Article 7, paragraph 4, stipulates that the headquarters of OPANAL “shall be in Mexico City”. Finally, Article 28 reflects in its text the compromise formula which, as already explained, overcame the most serious obstacle which confronted COPREDAL: the entry into force of the treaty.

The two Additional Protocols to the treaty have identical preambles. Their texts recall UN Resolution 1911 (XVIII) and state the conviction that the treaty “represents an important step towards ensuring the non-proliferation of nuclear weapons”. The texts also point out that the treaty “is not an end in itself but, rather, a means of achieving general and complete disarmament at a later stage”, and finally express the desire to contribute “towards ending the armaments race”. The operative parts of the protocols are naturally different from one another, although they have identical duration (the same as that of the treaty) and entry into force for the states which ratify each Protocol (the date of the deposit of the respective instruments of ratification).

Under Article 1 of Additional Protocol I, those extra-continental states which, de jure or defacto, are internationally responsible for territories lying within the limits of the geographical zone established by the treaty would, upon becoming parties to the protocol, agree “to undertake to apply the statute of denuclearization in respect to warlike purposes as defined in Articles 1, 3, 5 and 13 of the Treaty” to such territories.

One aspect which should be borne in mind is that this protocol does not give those states the right to participate in the General Conference or in the Council of the Latin American Agency. But neither does it impose on those states any of the obligations relating to the system of control established in Article 14 (providing for semi-annual reports), in Article 15 (providing for special reports), and in Article 16 (providing for special inspections). In addition, the prohibition of reservations included in the treaty’s Article 27 is not applicable to the protocol. Thus, in the protocol the necessary balance has been preserved between rights and obligations: although the rights are less extensive, the obligations are also fewer.

With regard to Additional Protocol II, the obligations assumed by the nuclear powers parties to the protocol are stated in its Articles 1 through 3 in the following terms:

Respecting “in all its express aims and provisions” the “statute of denuclearization of Latin America in respect of warlike purposes, as defined, delimited and set forth” in the Treaty of Tlatelolco.

Not contributing “in anyway to the performance of acts involving a violation of the obligations of Article 1 of the Treaty in the territories to which the Treaty applies”.

Not using or threatening to use “nuclear weapons against the contracting parties of the Treaty”.

III. Conclusions

The importance of nuclear-weapon-free zones has been emphasized several times by the United Nations. The General Assembly in its Resolution 3472 B (XXX) of 11 December 1975 stated that “nuclear-weapon-free zones constitute one of the most effective means for preventing the proliferation, both horizontal and vertical, of nuclear weapons and for contributing to the elimination of the danger of a nuclear holocaust”.

Subsequently, on 30 June 1978 the General Assembly, in the Program of Action adopted by consensus as its first special session devoted to disarmament, stressed the significance of the establishment of nuclear-weapon-free zones as a disarmament measure.

The weight which the international community attaches to the Latin American nuclear-weapon-free zone was manifest from the very moment the Treaty of Tlatelolco was presented to the General Assembly. In its Resolution 2286 (XXII) of 5 December 1967, the General Assembly welcomed it “with particular satisfaction” and declared that it “constitutes an event of historic significance in the efforts to prevent the proliferation of nuclear weapons and to promote international peace and security”. Such weight has been once again evidenced when, in the general debate of the first special disarmament Assembly, no less than forty-five States had supportive comments for the treaty.

The Treaty of Tlatelolco has shown the crucial importance of ad hoc preparatory efforts, such as those carried out for two years by COPREDAL, in attaining the desired goal. Furthermore, the Latin American nuclear-weapon free zone which is now nearing completion has become in several respects an example which, notwithstanding the different characteristics of each region, is rich in inspiration. It provides profitable lessons for all states wishing to contribute to the broadening of the areas of the world from which those terrible instruments of mass destruction that are the nuclear weapons would be forever proscribed, process which, as unanimously declared by the General Assembly in 1978, “should be encouraged with the ultimate objective of achieving a world entirely free of nuclear weapons”.

* The author of this study presided over the “Preliminary Session on the Denuclearization of Latin America” (REUPRAL) held in 1964, as well as over the four sessions of the “Preparatory Commission for the Denuclearization of Latin America” (COPREDAL), held from 1965 to 1967, which made possible the elaboration and approval of the Treaty for the Prohibition of Nuclear Weapons in Latin America known as the Treaty of Tlatelolco. He was also Chairman of the “Preliminary Meeting” (REOPANAL), contemplated in Article 28 (3) of the Treaty and of the two parts of the first session of the General Conference of the Agency for the Prohibition of Nuclear Weapons in Latin America (OPANAL) which took place in 1969 and 1970, respectively.

1. At the Dumbarton Oaks Conference, August-October 1944, the United States, Great Britain, China and the USSR drafted specific proposals for what was to be the Charter of the United Nations.