It's a scene replayed often along the southwestern border of the U.S. Helicopter-borne Border Patrol agents cruising above a stretch of harsh Sonoran Desert known to immigrants as la puerta dorada (the golden door) spot a white Ford F-150 pickup truck packed with a dozen Mexicans barreling northward on Arizona's State Road 286. The migrant smuggler driving the truck whirls around, floors the accelerator, and zips 20 miles back to the border, swerving wildly to avoid tire-puncturing metal spikes placed on the two-lane highway. Two helicopters and five patrol cars follow in hot pursuit. The truck screeches to a halt at a brand-new border fence, and four of the men, including the suspected smuggler, scramble onto the cab's roof, shimmy over the barrier, and drop to the Mexican side.
The 18-foot fence—an impressive-looking series of vertical steel bars, three inches in diameter, filled with concrete and reinforcing rods—is a prototype designed especially to thwart climbers. As shotgun-toting agents arrest the eight migrants left behind, the four who got away watch from a hilltop on the Mexican side until a Chevy Suburban pulls up next to them, doubtless ready for the next run around the seven-mile-long barrier. "Border fences don't keep people out—they just slow them down," muses Jesús Rodríguez, a 15-year Border Patrol veteran, after the Jan. 23 chase near Sasabe, Ariz., one of the most popular crossing points for migrants trying to get to prized jobs as cooks, nannies, and construction workers. "People who want to get into the U.S. really badly won't let something like a fence get in the way."