YUMA, Ariz.—Every night at the “Yuma gap,” where the California, Arizona, and United States-Mexico borders meet along the Colorado River, dozens or hundreds of migrants huddle in the thick brush waiting for their chance to come to America for a better life—a promise Mexican drug cartels have sold them for $500 to $5,000 a head.
But that dream is still more than 100 yards away down a steep embankment across the river to where the 30-foot tall iron border wall ends at the Cocopah Indian Reservation.
Behind them, the cartels patrol a road along the riverbank. They drop off two or three carloads of migrants at a time near a narrow part of the river about a half-mile trek to an 8-foot-wide gap between the wall and barricades designed to block vehicles—not people….