In this Arizona town, business has slowed as a border crackdown ramps up

Immigration may top many voters' concerns, but residents here say it's the economy, not security, that worries them

For the past three decades, Ernesto Tapia's neon-lit electronics shop in Nogales, Arizona, had been the prevailing regional destination for gearheads seeking tricked-out car stereos.

Some of his loyal customers would drive down to the small town on the US-Mexico border from Tucson, but most made the trek from the Mexican states of Sonora and Sinaloa.