Guillermo Martínez could see the promised land of Southern California from the cramped three-bedroom house he shared here with his mother, his wife and two small children. The smooth, dry hills of San Diego County lay just beyond the slum where he lived, past the cinder block shacks, the garbage-strewn streets and rusted-out cars, past the corrugated steel fence that marks the border, and past the taller metal-columned fence put up in the 1990’s to stop people like him from crossing. Full Story