On a sweltering summer evening in southern Arizona, dozens of carpet-soled moccasins lie along the portico of a ranch 20 miles from Mexico, serving as a reminder of one of the biggest problems on the border: not illegal immigration, but drug trafficking.
Interrupted only by the cicadas, Jim Chilton, a fifth-generation rancher, and his wife Sue explain that Mexican drug mules, who routinely traverse their 50,000 acres of land, cover the soles of the moccasins — which are then worn over shoes — with carpet to avoid leaving tracks that US border agents could follow. . . .