The United States involvement in the Mexican Revolution was varied and seemingly contradictory, first supporting and then repudiating Mexican regimes during the period 1910–1920. For both economic and political reasons, the U.S. government generally supported those who occupied the seats of power, but could withhold official recognition. The U.S. supported the regime of Porfirio Díaz (1876–1880; 1884–1911) after initially withholding recognition since he came to power by coup. In 1909, Díaz and U.S. President Taft met in Ciudad Juárez, across the border from El Paso, Texas. Prior to Woodrow Wilson's inauguration on March 4, 1913, the U.S. Government focused on just warning the Mexican military that decisive action from the U.S. military would take place if lives and property of U.S. nationals living in the country were endangered. President William Howard Taft sent more troops to the US-Mexico border but did not allow them to intervene directly in the conflict, a move which Congress opposed. Twice during the Revolution, the U.S. sent troops into Mexico, to occupy Veracruz in 1914 and to northern Mexico in 1916 in a failed attempt to capture Pancho Villa. U.S. foreign policy toward Latin America was to assume the region was the sphere of influence of the U.S., articulated in the Monroe Doctrine. However the U.S. role in the Mexican Revolution has been exaggerated. It did not directly intervene in the Mexican Revolution in a sustained manner.
During Díaz's long rule, he implemented policies aimed at modernization and economic development, inviting foreign entrepreneurs to invest in Mexico. The regime passed laws favorable to investors. American business interests invested large amounts of capital, particularly along the U.S.-Mexico border, during the decades of Díaz's rule. There was close economic cooperation between the two governments, which was predicated on Diaz's cooperation with US investors. In 1908 Díaz stated he would not run for re-election in 1910; the statement gave rise to politicking of potential candidates. Díaz reversed himself, ran for re-election, and jailed the leading opposition candidate, Francisco I. Madero. Madero escaped Mexico and took refuge in San Antonio, Texas, and called for nullification of the 1910 elections, declared himself as provisional president, and asked for support from the Mexican people. His Plan of San Luis Potosí sparked revolutionary uprisings, particularly in Mexico's north. The U.S. stayed out of the unfolding events until March 6, 1911, when President William Howard Taft mobilized forces on the U.S.-Mexico border. "In effect this was an intervention in Mexican politics, and to Mexicans it meant the United States had condemned Díaz."
