In 1916, following the raids of Mexican bandit/revolutionary Pancho Villa into New Mexico and Arizona, the entire National Guard, more than 150,000 strong, was federalized for a year and stationed along the 2,000 mile Mexican border in California, Arizona, New Mexico, and Texas. Ninety years later, tens of thousands of Army and Air National Guard members returned to the same border, to perform a mission which, considering the timespan, was remarkably similar.
By 2006, migrants from Central America and Mexico, drawn by a booming U.S. economy, were crossing the border into the United States in unprecedented numbers. Construction of a fence along the California-Mexico border had driven the migrants eastward, and southern Arizona, large stretches of it unpopulated, saw hundreds of crossings each day. Governor Janet Napolitano called out the Arizona National Guard to assist the beleaguered Border Patrol, and governors of the three other border states joined her in calling on the Federal government to enforce the nation’s immigration laws and stem the tide of illegal activity along the border.
On May 15th, 2006, President George W. Bush announced the initiation of "Operation Jump Start," a plan to use National Guard troops to assist the Border Patrol in restoring order to the region. The troops would operate under the terms of Memorandums of Agreement signed by the four border-state governors. While the troops would not participate directly in law enforcement or in apprehending migrants, they would be armed.
For the next two years, up to 6,000 National Guard soldiers and airmen at a time rotated in contingents throughout the Southwest. They monitored electronic surveillance systems, manned isolated outposts, and flew helicopters equipped with sophisticated radar systems, their presence freeing up hundreds of Border Patrol agents to perform the actual apprehension of illegal migrants and drugs. Guard engineers built dozens of roads, particularly in the mountains of southeastern Arizona, increasing the Border Patrol’s mobility and earning the gratitude of its agents, who still patrol this rugged country on horseback as they have done since the 1920s.
When Operation Jump Start concluded in July 2008, over 30,000 Army and Air Guard personnel from units in all 54 states, territories, and the District of Columbia had served on the border. As in 1916-17, the presence of the National Guard along the border made a difference, and the number of migrant apprehensions decreased after their deployment.