SEPARATED: This 2006 file photo shows a border fence that separates the U.S., left, from Mexico in downtown Nogales, Ariz. A spate of drug-related killings the past few months in Nogales, Mexico, is keeping some residents in its U.S. sister city from crossing the border.
By Mark Scarp, contributing columnist
By Jerry Brown, contributing columnist
Guest Commentary by Bill Richardson
Guest Commentary by Shawn Thiele
By Mark Heller, Tribune