Latin America Nuclear Free Zone Treaty (1967)


Multilateral agreement signed by 24 Latin American countries banning the manufacture, acquisition, testing, deployment, or use of nuclear weapons in Latin America. Argentina has not yet ratified the treaty and Cuba is the only country that has neither signed nor ratified the treaty. This treaty is also known as the Treaty of Tlatelolco and entered into force on April 22, 1968.


The Treaty for the Prohibition of Nuclear Weapons in Latin America (also known as the Treaty of Tlatelolco) obligates Latin American parties not to acquire or possess nuclear weapons, nor to permit the storage or deployment of nuclear weapons on their territories by other countries. Besides the agreement among the Latin American countries themselves, there are two Additional Protocols dealing with matters that concern non-Latin American countries. Protocol I involves an undertaking by non-Latin American countries that have territories in the nuclear-free zone. Protocol II involves an undertaking by those powers which possess nuclear weapons. The United States is a party to both protocols.

The United States has favored the establishment of nuclear-weapon-free zones where, inter alia , they would limit the spread of nuclear weapons; they would not disturb existing security arrangements; provisions exist for adequate verification; the initiative for such zones originates in the geographical area concerned; and all states important to the denuclearization of the area participate. Considering that Soviet proposals for the denuclearization of Central Europe and other areas have not met these criteria, the United States has opposed them. From the start, however, the United States supported and encouraged Latin American countries in this undertaking.

In mid-1962, the Brazilian representative to the UN General Assembly proposed making Latin America a nuclear-weapon-free zone. At the seventeenth regular session of the General Assembly, during the October Cuban missile crisis, a draft resolution calling for such a zone was submitted by Brazil and supported by Bolivia, Chile, and Ecuador. While asserting support for the principle, Cuba stipulated certain conditions, including the requirement that Puerto Rico and the Panama Canal Zone be included in the zone, and that foreign military bases, especially Guantanamo Naval Base, be eliminated. The draft resolution was not put to a vote at the General Assembly that year.

On April 29, 1963, at the initiative of the President of Mexico, the Presidents of five Latin American countries -- Bolivia, Brazil, Chile, Ecuador, and Mexico -- announced that they were prepared to sign a multilateral agreement that would make Latin America a nuclear-weapon-free zone. On November 27, 1963, this declaration received the support of the UN General Assembly, with the United States voting in the affirmative.

The Latin American nations followed this initiative by extensive and detailed negotiations among themselves. At the Mexico City Conference (November 23-27, 1964) a Preparatory Commission for the Denuclearization of Latin America was created, with instructions to prepare a draft Treaty. Important differences among the Latin American countries emerged over questions of defining the boundaries of the nuclear-weapon-free zone, transit guarantees, and safeguards on peaceful nuclear activities.

On February 14, 1967, the Treaty was signed at a regional meeting of Latin American countries at Tlatelolco, a section of Mexico City. On December 5, 1967, the UN General Assembly endorsed it by a vote of 82-0 with 28 abstentions, the United States voting in support of the Treaty. As of January 1, 1989, the Treaty had entered into force for 23 Latin American states. Belize and Guyana were not invited to accede to the Treaty because a special regime is foreseen for those political entities whose territories are wholly or partially the subject of disputes or claims by an extracontinental state and one or more Latin American states. When all eligible states ratify the Treaty, it will enter into force for all of them, as specified in Article 28. Alternatively, under that article, any Latin American state may bring the Treaty into force for itself at any time by waiving that provision.

Source: Department of State