The Pancho Villa Expedition—now known officially in the United States as the Mexican Expedition, but originally referred to as the "Punitive Expedition, U.S. Army"—was a military operation conducted by the United States Army against the paramilitary forces of Mexican revolutionary Francisco "Pancho" Villa from March 14, 1916, to February 7, 1917, during the Mexican Revolution of 1910–1920. The expedition was launched in retaliation for Villa's attack on the town of Columbus, New Mexico, and was the most remembered event of the Mexican Border War. The declared objective of the expedition by the Wilson administration was the capture of Villa. Despite locating and defeating the main body of Villa's command who were responsible for the Columbus raid, U.S. forces were unable to achieve Wilson's stated main objective of preventing Villa's escape. The active search for Villa ended after a month in the field when troops sent by Venustiano Carranza, the head of the Constitutionalist faction of the revolution and then head of the Mexican government, resisted the U.S. incursion. The Constitutionalist forces used arms at the town of Parral to resist passage of a U.S. Army column. The U.S. mission was changed to prevent further attacks on it by Mexican troops and to plan for the possibility of war. When war was averted diplomatically, the expedition remained in Mexico until February 1917 to encourage Carranza's government to pursue Villa and prevent further raids across the border. Background Trouble between the United States and Pancho Villa had been growing since October 1915, when the United States government officially recognized Villa's rival and former ally Venustiano Carranza as head of the government of Mexico. The U.S. also provided rail transportation through the United States, from Eagle Pass, Texas to Douglas, Arizona, for the movement of more than 5,000 Carrancista forces to fight Villa at the Battle of Agua Prieta; Villa's seasoned División del Norte was smashed. Feeling betrayed, Villa began attacking U.S. nationals and their property in northern Mexico. On November 26, 1915, Villa sent a force to attack the city of Nogales and in the course of the ensuing battle, engaged with American forces before withdrawing. On January 11, 1916, sixteen American employees of the American Smelting and Refining Company were removed from a train near Santa Isabel, Chihuahua, and summarily stripped and executed. Brigadier General John J. Pershing, commanding the district headquartered at Fort Bliss, Texas, received information that Villa with