But blindness to the unintended consequences is a hallmark of immigration politics. Decades of militarizing the border — without visa reforms to improve the legal immigrant flow — have sealed people out. They have also sealed them in. Immigrants who would have been inclined to work here and go home are induced to stay. They put down roots, and try to bring their families over.
When crossing the border gets more treacherous, the people trying to cross fall into the hands of criminals — smuggling operations that already have lucrative businesses moving drugs and money over the border. Smugglers are profiting mightily from the fear that propels children north and the fear that locks our country down.
Republicans are feeding the cycle, stoking panic about a border under assault, even to the point of demanding that Mr. Obama call out the National Guard. Nativist protesters are blocking buses of migrants in places like Murrieta, Calif. Homegrown militias are issuing calls to arms. Illegal border crossings, meanwhile, are still lower than they have been in years. The besieged border is a myth, and the arrival of a few thousand weary refugee children on buses does not make the myth true.