U.S. Embassy & Consulates
in Mexico

1830–1860: Diplomacy and Westward Expansion

During this period, the United States pursued a policy of expansion based on “manifest destiny,” the ideology that Americans were in fact destined to extend their nation across the continent. The United States even proved to be willing to go to war to secure new territories. While it managed to negotiate an agreement with Great Britain to secure the Oregon territory, acquiring the valuable territory south of it—including California and its important Pacific harbors—required the use of force, and, in 1845, the United States embarked on its first offensive war by invading Mexico.

The Annexation of Texas

The Annexation of Texas, the Mexican-American War, and the Treaty of Guadalupe-Hidalgo, 1845–1848 During his tenure, U.S. President James K. Polk oversaw the greatest territorial expansion of the United States to date. Polk accomplished this through the annexation of Texas in 1845, the negotiation of the Oregon Treaty with Great Britain in 1846, and the conclusion of the Mexican-American War in 1848, which ended with the signing and ratification of the Treaty of Guadalupe-Hidalgo in 1848.

French Intervention in Mexico & the American Civil War

Throughout the period of French intervention, the overall U.S. policy was to avoid direct conflict with France, and voice displeasure at French interference in Mexican affairs, but ultimately to remain neutral in the conflict. After 1866, U.S. Secretary of State William Henry Seward provided more direct support for Juárez, while French willingness to withdraw de-escalated Franco-American tensions. Although U.S. support for Juárez improved U.S.-Mexican relations temporarily, disputes over policing of the border under Secretary of State William Evarts would erode the good will built during Seward’s tenure.

Good Neighbor Policy, 1933

President Franklin Delano Roosevelt took office determined to improve relations with the nations of Central and South America. Under his leadership the United States emphasized cooperation and trade rather than military force to maintain stability in the hemisphere.

Mexican Expropriation of Foreign Oil, 1938

On March 18, 1938, Mexican President Lázaro Cárdenas signed an order that expropriated the assets of nearly all of the foreign oil companies operating in Mexico. He later created Petróleos Mexicanos (PEMEX), a state-owned firm that held a monopoly over the Mexican oil industry, and barred all foreign oil companies from operating in Mexico. The U.S. Government responded with a policy that backed efforts by American companies to obtain payment for their expropriated properties but supported Mexico’s right to expropriate foreign assets as long as prompt and effective compensation was provided.