Latin America's Place in the Third Nuclear Age

Federico Canas Velasco | Latin America Fellow

Image sourced from Milton Martínez / Secretaría de Cultura de la Ciudad de México via Wikimedia Commons.

The 6th and 9th of August 2025 marked the 80th anniversary of the atomic bombings of Hiroshima and Nagasaki, the only occasions upon which nuclear weapons have been used in war. These attacks ended World War II and launched the nuclear age, triggering an arms race that has shaped global power dynamics for eight decades. As nuclear tensions escalated, Latin American leaders made history in 1967 with the Treaty of Tlatelolco, establishing the world’s first nuclear-weapon-free zone (NWFZ) and setting a model for others to follow. Following Latin America's lead, the creation of other NWFZs helped curb the global spread and stockpiling of nuclear weapons throughout the Cold War.

Today, progress has stalled. The world is now entering a “third nuclear age,” defined by multipolar rivalry, the collapse of arms control treaties, and renewed threats around the globe. As it enters this new era, Latin America has the precedent and potential to once again shape the global conversation on denuclearisation. However, in order to stand strong on the world stage as it did once before, the region must first overcome its fragmented state and reassemble into a united front.

The Legacy of Tlatelolco

In the aftermath of the 1962 Cuban Missile Crisis, Latin America exhibited a rare display of regional unity. Amid rising nuclear fears, states chose diplomacy over escalation, culminating in the 1967 Treaty of Tlatelolco, the first NWFZ in a populated area. Spearheaded by Mexican diplomat Alfonso García Robles, the treaty institutionalised the region’s anti-nuclear stance and established the Agency for the Prohibition of Nuclear Weapons in Latin America and the Caribbean (OPANAL), a permanent regional body to verify compliance and uphold the region’s nuclear-free status.

Tlatelolco’s legacy became a model for other NWFZs across the globe, inspiring the Treaty of Rarotonga (South Pacific), Bangkok (Southeast Asia), Pelindaba (Africa), Semipalatinsk (Central Asia), and Mongolia’s NWFZ. By successfully harnessing regional cooperation and legal mechanisms rather than military alliances to advance disarmament, Latin America contributed to the global decline in nuclear weapons after the Cold War. The region maintained a consistent presence in disarmament forums, with many of its states supporting the Treaty on the Prohibition of Nuclear Weapons (TPNW). Through such actions, Latin America asserted that nuclear war poses an existential threat not just to nuclear states, but to all. However, cracks are beginning to emerge within this regional unity.

A Fragmented Nuclear Tradition

In a significant departure from its longstanding tradition of peaceful nuclear disarmament, Argentina openly supported United States (US) airstrikes on Iranian nuclear sites in June 2025. This move shocked the region and was condemned by several Latin American governments, including Colombia, Chile, Mexico, and Venezuela.

Argentina’s actions reflect a deliberate realignment with US strategic thinking, prioritising unilateral security actions over diplomatic and legal channels to address nuclear threats. Indeed, at the United Nations (UN) in November 2024, it joined Israel as the only other country to vote against a resolution supporting new NWFZs, breaking with decades of support for such initiatives. 

This shift in Argentina's foreign policy is indicative of a broader fragmentation within Latin America's once unified stance on nuclear disarmament. Such fragmentation is not only a matter of diplomatic alignment but also a growing divergence in national priorities. 

The refusal of Argentina and Brazil, South America’s only countries with nuclear programs, to sign the International Atomic Energy Agency’s (IAEA) Additional Protocol exemplifies this point. The Additional Protocol, a contemporary mechanism for more intrusive inspections, is a measure that Brazil and Argentina reject on the grounds of national sovereignty and a belief that their existing bilateral agency, the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC), is sufficient. Their preference for a bilateral framework over a multilateral one undermines the collective spirit embodied by the Treaty of Tlatelolco. 

Ultimately, this shift away from collective regional cooperation on nuclear issues, characterised by a focus on national interests and sovereignty, demonstrates how Latin America's nuclear front has eroded over time. The shift away from the regional norm is a key obstacle that the region must overcome to regain the model of cooperation that underpinned its leadership.

Reviving Regional Leadership

The success of the Treaty of Tlatelolco during the Cold War was not driven by a single dominating actor, but by the region's willingness to set aside divisive issues to focus on the shared goal of a nuclear-free Latin America. To reclaim its cooperation, the region must adopt this same pragmatic strategy.

A critical first step is for the region's two nuclear pioneers, Brazil and Argentina, to set a new standard for cooperation. By prioritising a collective vision over their individualistic national interests, they could demonstrate renewed unity, starting with a joint commitment to the IAEA’s Additional Protocol. Signing the protocol would signal that their long-standing desire for technological autonomy is secondary to the region's collective security. This renewed commitment to a shared vision would further strengthen the institutions that coordinate regional action, such as OPANAL and Community of Latin America and Caribbean States (CELAC), by restoring their credibility and empowering them with a clear mandate for action on disarmament.

By once again prioritising legal norms and dialogue, Latin America can actively challenge the increasing normalisation of nuclear threats and reclaim its legacy as a disarmament leader. As arms races intensify, the region has a unique opportunity to once again model a different path. A reunited Latin America can demonstrate that peace is better secured through cooperation and dialogue than the threat of destruction.

Federico Canas Velasco is the Latin American Fellow for Young Australians in International Affairs. He is completing his final year of a Bachelor of Arts and Advanced Studies in International and Global Studies at the University of Sydney, majoring in Spanish and Latin American Studies.

Born in Australia to Venezuelan parents, Federico's interest in Latin America stems from his proud heritage as well as his academic exploration of the region's cultural, political, and historical complexities. This interest was further enriched when he studied abroad at la Universidad Carlos III de Madrid. Federico looks forward to this Fellowship as an opportunity to combine his research interests with his personal experience to contribute meaningful analysis on Latin America's future amid shifting global dynamics.

Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect those of Young Australians in International Affairs. All content is original, and no plagiarism has been used in the preparation of this article.