From the Treaty of Guadalupe Hidalgo to NAFTA, five agreements that marked the history of US relations with Latin America.
TRADE AND DIPLOMACY
Five US treaties that shaped Latin American history
Though Donald Trump has made Washington’s influence over Latin America more visible than usual in 2025, the United States has been shaping the region’s political and economic realities for more than two centuries. In this end-of-year special, we revisit five diplomatic agreements signed by the US that transformed Latin America, for better or for worse, and explain why they continue to matter decades — and in some cases centuries — later.
- Treaty of Guadalupe Hidalgo (1848)
Often dismissed as ancient history, the Treaty of Guadalupe Hidalgo still underpins US-Mexican relations. It ended a two-year war between the two countries, but at the cost of Mexico ceding more than half of its territory to the US — a history-altering loss embraced in Washington as the fulfillment of the expansionist creed known as “Manifest Destiny.”
The lands transferred included what are now California, Nevada, Utah and New Mexico, most of Arizona and Colorado, and parts of Oklahoma, Kansas and Wyoming. Mexicans living in those territories were promised US citizenship and legal protections. Yet the legacy of the treaty remains politically charged, resurfacing whenever debates over the border, migration or sovereignty intensify.
- Spanish-American Peace Treaty (1898)
If the war with Mexico marked the continental expansion of the US, the Spanish-American War ushered in an era of overseas empire. After backing Cuban insurgents against Spanish rule, US naval power forced Madrid to relinquish its remaining colonial claims under the Treaty of Paris, signed in 1898.
Cuba emerged as an independent republic in 1902, but under intense US tutelage. The treaty also transferred Puerto Rico and Guam to Washington and paved the way for the US conquest of the Philippines soon afterward, signaling America’s arrival as a global imperial power.
- Panama Canal Treaty (1903)
Cuba was not the only independence movement to benefit from US support. Just 15 days after Panama seceded from Colombia in 1903, the fledgling nation signed the Hay-Bunau-Varilla Treaty with Washington. The agreement granted the US perpetual control over a 10-mile-wide canal zone, in exchange for USD 10 million and an annual payment.
The canal combined a geopolitical coup with a monumental engineering achievement. It transformed global trade routes and underpinned US naval dominance during both world wars. It also helped turn Panama into one of Central America’s more prosperous countries. Nationalist pressure, however, eventually led to the Torrijos-Carter Treaties of 1977, which set the return of the canal to Panama on Dec. 31, 1999.
Though it no longer controls the waterway, the US still considers it strategically vital — a point underscored by Trump’s pressure on Panama to remove Chinese companies from the canal area.
- The Organization of American States (1948)
After emerging from World War II as a global hegemon, the US consolidated its leadership in the Western Hemisphere by creating the Organization of American States in 1948. Meeting in the Colombian capital of Bogotá, the US and every independent Latin American country at the time (20 in total) signed a charter pledging to promote peace, security, democracy and development across the region.
One of its most contentious provisions established that an armed attack against any member could trigger a collective response, a clause that opened the door to US-led diplomatic and military pressure. Over the decades, the OAS has been used against governments ranging from Fidel Castro’s Cuba to Rafael Trujillo’s Dominican Republic.
The OAS’s priorities have shifted with political currents in Washington: anti-communism dominated in the 1960s and 1970s, human rights gained prominence during the Carter administration, and election monitoring and governance took center stage after the Cold War. Controversy has followed it throughout, most recently over its role in the events leading to the ouster of Bolivia’s President Evo Morales in 2019.
- NAFTA (1994)
Last but not least, the North American Free Trade Agreement fundamentally reshaped economic ties between Mexico, the US and Canada. By eliminating tariffs and other barriers, NAFTA encouraged cross-border investment, strengthened intellectual property protections and established mechanisms to resolve trade disputes.
The agreement proved to be a significant boost for Mexican manufacturing, providing unparalleled access to the US market. But it also provoked fierce political backlash. On Jan. 1, 1994 — the day NAFTA came into force — an indigenous uprising in Mexico’s southern state of Chiapas, led by the Zapatista Army of National Liberation, announced itself to the world.
The rebellion became an enduring symbol of resistance to globalization; the influence of this movement is still felt today.