1967 Tlatelolco Treaty

The treaty came in the wake of the fear of horizontal nuclear proliferation, and a new ethical code was desperately needed after the damages seen in Nagasaki and Hiroshima in 1945. The tensions between the US and the Soviet Union were rising, and the threat of a third world war seemed imminent. The Cuban Missile Crisis of 1962 was proof the two blocs were willing to use their neighbouring regions as pawns of war, and the middle states needed to take measures to protect themselves. The 1963 Partial Test Ban Treaty was signed by both the Soviet Union and the US, which prohibited the testing of nuclear weapons in outer space, underwater or in the atmosphere, and was a step towards disarmament in a political environment seemingly aimed at exponential proliferation. War was becoming more likely, and although Cuba opted to not sign the treaty until 2002, Latin America deemed it necessary to act on being a nuclear weapon free zone to avoid the fallout of being so close to a Cold War superpower.

Costa Rica first brought up the idea of nuclear arms control in the Latin American region in 1958 Nuclear Threat Initiative, 'Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (LANWFZ) (Tlatelolco Treaty)', 2016, and at the UN General Assembly during the October Cuban Missile Crisis. A draft resolution calling for such a zone was submitted by Brazil in 1962, and supported by Bolivia, Chile, and Ecuador. In 1963, Bolivia, Brazil, Chile, Ecuador, and Mexico announced they were ready to sign a multilateral agreement that would make Latin America a Nuclear Weapon Free Zone. In 1964, a Preparatory Commission for the Denuclearization of Latin America was created to discuss and negotiate finer details of the treaty, such as exact boundaries of the proposed zone, and safeguards on peaceful nuclear activities. 'Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (Treaty of Tlatelolco), US Department of State. A meeting was held in the Tlatelolco suburb of Mexico City in February 1967, where Latin America regionally signed the treaty, and on 5 December of that same year, the UN General Assembly endorsed it by a vote of 82-0 with 28 abstentions. The United States voted in support of the treaty, and had continuously backed it in its process, despite rejecting the Soviet’s proposal of a denuclearized central Europe. 'Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (Treaty of Tlatelolco)', US Department of State.  The US set up a list of criteria for framing the future nuclear free zones and provisions to maintain no infringement of national or international rights. Their main concern was keeping the scope to promote non-proliferation, while still protecting their rights for nuclear weapons. T. Graham, 'The Treaty of Tlatelolco: Its Role in the International Regime of Nonproliferation', Agency for the Prohibition of Nuclear Weapons in Latin American and Caribbean (OPANAL), 1997. Other than that, there was no overwhelming opposition to the provisions.

Although Antarctica was officially the first nuclear weapon free zone under the 1959 Antarctic Treaty, this was the first of its kind over a populated area. It created a new discourse of global non-proliferation, affirming that the topic did not only need to centre around the USSR and the United States; surrounding regions could have a voice in the debate as well. And to add to its legacy, whereas the NPT did not properly define a 'nuclear weapon', the Treaty of Tlatelolco did so (in Article 5), making it still used as a framing device for a potential nuclear weapon free zone in the Middle East. M.I. Shaker, 'The Middle East Issue: Possibilities of a Nuclear-Weapons–Free Zone', Organismo Para La Proscripcion de Las Armas Nucleares En La América Latina Y El Caribe (Basel Peace Office), 2004. It also reaffirmed Latin America as a 'Zone of Peace'. Nuclear Threat Initiative, 'Treaty for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (LANWFZ) (Tlatelolco Treaty)', 2016. The peacekeeping effort was recognized on an individual level as well, as the Mexican diplomat Alfonso García Robles received the Nobel Peace Prize in 1982 for his involvement. T. Graham, 'The Treaty of Tlatelolco: Its Role in the International Regime of Nonproliferation', Agency for the Prohibition of Nuclear Weapons in Latin American and Caribbean (OPANAL), 1997.

The Agency for Prohibition of Nuclear Weapons in Latin America (OPANAL) was created after the adoption of the treaty to build confidence in the continuous implementation of the obligations using IAEA safeguards, with regular meetings of the states parties and transparency efforts.

Protocol I is an agreement by non-Latin American countries that have territories in the nuclear-free weapon zone to not store or test any nuclear weapons in the region. Countries involved include the United Kingdom (signed in 1967), the Netherlands (signed in 1968) , France (signed last in 1979), and the United States (signed in 1977). It built trust outside of the Latin American signatories to respect the multilateral agreement of territory holders in the geographical zone. An example of the implications of this provision is that French Guiana, under the ratification of France, is able to denuclearize, falling into the jurisdiction of the region.

Protocol II involves an agreement by those powers which possess nuclear weapons to regard them as peaceful states, and not threaten to use nuclear weapons against the countries under the treaty, thus creating a dialogue of mutual trust between weapon and non weapon holding states. This includes France (signed in 1973), the United Kingdom (1967), the United States (signed in 1968), China (signed in 1973), and the Russian Federation (1978). 

In July 1990, the title and all necessary articles were changed to include 'and the Caribbean'.