A peasant leader in Guatemala asked last year if I could help him get several men deported from the United States. Why? They were no longer sending money to their children, and their wives hoped they could be deported back to their responsibilities. When my friend took this petition to the Guatemalan foreign ministry, he was informed that its mission is to support migrants to the U.S., not extradite them.

The episode comes to mind as tens of thousands of unaccompanied minors, mothers and small children pile up on America's...