How A Border Wall Could Stop Mexicans From Leaving The U.S.

President Trump on Tuesday night vowed to start his proposed wall along the U.S.- Mexico border "ahead of schedule," saying that it would be an "effective weapon against drugs and crime."

Here & Now's Eric Westervelt (@Ericnpr) speaks with Stanford professor Ana Raquel Minian, who says more Mexicans have been leaving the U.S. in recent years than coming in. She believes the wall could have the unintended consequence of discouraging more from leaving.