Thirty years ago—three decades before any 21st-century president riled crowds by promising to build a wall—photographer James Whitlow Delano wondered why the U.S.-Mexico border was so fraught. Here were two countries at peace for over a century. But the divide between them was enough to warrant a series of border fences and angry debates about how to stop illegal immigrants.

Thirty years later, the debate, and the region, have intensified. The patches of fence have since been fortified by drones, scanners, and guards. Smugglers who once charged a few hundred dollars to cross the border in the carved-out floor of a truck or in a mad dash across the Sonoran Desert have been replaced by expensive coyotes and deadly cartels, whose