When he was new in "blue," Robert Owens was the scourge of East Los Angeles junkies, racking up record-breaking numbers of heroin arrests. But even then, the young Los Angeles County sheriff's deputy wondered if all the collars and the time and resources it took to make them were making any difference. Those doubts only grew during the rest of his 38 years in law enforcement, including his 22 years as police chief in gritty Oxnard, Calif. Today, at 74, Owens is an outspoken proponent of ending America's drug war, which has been waged for nearly four decades at an...