Immigration Reform May Depend on Catching More Illegal Border Crossers

To patrol the remote 262-mile stretch of the U.S.-Mexico border south of Tucson, agents monitor surveillance cameras, sensors, and infrared scopes in the desert. They stalk through mountainous wilderness on foot and horseback. They also search for footprints. The agents try to identify if the shoes that formed the prints are sneakers, work boots, or other footwear; the objective is to match them with shoes worn by people caught crossing the border illegally. (The agents regularly sweep the desert floor clean so they can spot fresh tracks.)

The footprints that don’t match up, along with other evidence of crossers they spot but don’t catch, are counted as “gotaways.” Agents compare the number of gotaways to the number of people turned back or detained; the result is a percentage used to gauge the security of the border. As Manuel Padilla Jr., chief patrol agent for the area, puts it, tallying the number of people who slipped through “is not an exact science.”