On March 15, 1916, General Pershing and 15,000 troops chased Pancho Villa into Mexico. From the article:
"Punitive Expedition in Mexico, 1916-1917
The Punitive Expedition into Mexico that the United States Government undertook in 1916 against Mexican Revolutionary leader Pancho Villa threatened to bring the United States and Mexico into direct conflict with one another. However, careful diplomatic maneuvering by Mexican President Venustiano Carranza and U.S. President Woodrow Wilson successfully resolved the crisis.
Pancho Villa, the Mexican revolutionary leader who controlled much of northeastern Mexico during 1914 and 1915, experienced military setbacks after breaking with the Carranza government and being subjected to a U.S. arms embargo. The Wilson Administration supported Carranza as the legitimate Mexican head of state and hoped that U.S. support could end Mexican political instability during the revolutionary period. Prior to the Mexican Revolution, the U.S.-Mexico border had been only lightly policed. The instability of the revolution led to an increased U.S. military presence, while U.S. citizens along the border often sympathized or aided the various factions in Mexico. As part of a campaign against U.S. interests in Northern Mexico, Villa's forces attacked U.S. mining executives in Mexico on January 9, 1916, provoking public anger in the United States, especially in Texas. Pancho Villa's forces then raided the town of Columbus, New Mexico, on March 9, 1916, resulting in the death of sixteen Americans and much larger casualties for Villa's forces.
In response, the Wilson Administration decided to order a punitive raid into Mexico with the goal of capturing Pancho Villa. Because of earlier, more minor raids, Wilson had already considered ordering an expedition a cross the border, and so directed Newton Baker, the Secretary of War, to organize an expedition specifically to pursue Villa. Wilson also attempted to mollify Mexican President Venustiano Carranza by claiming that the raid was conducted "with scrupulous regard for the sovereignty of Mexico." Nevertheless, Carranza regarded Wilson's actions as a violation of Mexican sovereignty and refused to aid the U.S. expedition.
The task of capturing Villa was given to U.S. Army General John J. Pershing. Pershing's forces entered Mexico, but failed to capture Villa. Instead, they encountered significant local hostility, and engaged in a skirmish with Carrancista forces. In the meantime, Carranza, who had counted on U.S. support for his presidency, attempted to keep civil relations with the United States despite the raid. Likewise, in the face of mounting U.S. public pressure for war with Mexico, Wilson and Secretary of State Robert Lansing also wished to improve relations, and hoped that the issue of border raids could be solved by negotiations with the Carranza government.
Wilson selected U.S. Army Chief of Staff Hugh L. Scott to negotiate with the Mexican government representative Alvaro Obreg�n. Scott and Obreg�n entered into negotiations in Juarez and El Paso, but failed to produce an agreement on anything more concrete than further talks. Meanwhile, on May 6, another cross-border raid by Villista guerillas occurred in Glen Springs, Texas, causing more U.S. troops to enter into Mexico to pursue the raiders. Tensions flared again when U.S. troops pursuing Villa instead clashed with Carrancista forces at the Battle of Carrizal on June 21, resulting the in the capture of 23 U.S. soldiers. Demonstrators in Mexico marched in opposition to the U.S. expedition. Aware of Wilson's anger over the recent battle, Carranza wrote to Wilson on July 4, suggesting direct negotiations.
Wilson and Carranza agreed to the establishment of a Joint High Commission, which met at New London, Connecticut on September 6. Leading each country's respective delegations were Franklin K. Lane, U.S. Secretary of the Interior, and Luis Cabrera, an important advisor to Carranza. Other representatives from both governments represented the various parties. The Commission issued a statement on December 24, 1916 which stated that U.S. troops could remain in Mexico if their presence was necessary, but otherwise should withdraw. Carranza rejected the agreement, sensing that it allowed for an indefinite U.S. presence. However, the talks sufficed to ease tensions and the U.S. troops prepared for withdrawal and re-crossed the border on February 5, 1917.
The Punitive Expedition was one of several incidents during which the United States Government or its officials intervened directly in Mexican affairs during the Mexican Revolution. Concern over U.S. power and corporate control of Mexican natural resources would lead to further U.S.-Mexican disagreement over the nationalization of the oil industry in the 1920s."