TOHONO O'ODHAM NATION, AZ - JANUARY 19: Undocumented Mexican immigrants walk through the Sonoran Desert after illegally crossing the U.S.-Mexico border border on January 19, 2011 into the Tohono O'odham Nation, Arizona. The immigrants said they had wandered the desert lost for a week after crossing from Mexico into the vast Indian reservation at night. Exhausted, they requested the Border Patrol to pick them up and take them to the U.S.-Mexico border, from where they would return to their homes in the Mexican state of Sonora. They had come, they said, to reach Phoenix and find work in construction or landscaping. All said they had worked in Arizona before. (Photo by John Moore/Getty Images)