Washington Post:

By Joshua Partlow
March 11, 2015

LAREDO, Tex. — Last spring, as Central American children flooded into Texas in a way he had never seen in his three-decade career, Border Patrol agent Robert Harris decided to experiment.

His intelligence analysts estimated that 78 percent of the guides smuggling other migrants were Mexicans younger than 18 — teenagers often hired or conscripted by drug cartels that knew they would not be prosecuted if caught — and he wanted to attack this loophole.

“Why don’t we remove these juveniles from the smuggling cycle?” Harris, the outgoing commander of the Laredo sector of U.S. Customs and Border Protection, recalled thinking.

Now, as a result of that decision, young Mexicans are being held for months without charge in shelters across the United States, sometimes without their parents’ knowledge. Since the program began in May, 536 juveniles have been held — 248…