
Black line is illegal immigrants who enter US without documents; grey line is unauthorized immigrants who enter legally but overstay their visas
Donald Trump has proposed building an impenetrable wall along the Mexican border to halt illegal immigration while hunting down and deporting the estimated 11 million unauthorized immigrants already in the United States.
My question: What would this cost?
Anybody can climb over a wall, so a barrier, to be effective, would have to be guarded, like the Berlin Wall. Maybe it would be possible to use electronic surveillance, perhaps from drones, to detect illegal crossers, but it would still cost a lot of money and require a lot of people.
Furthermore a wall would not be sufficient to secure U.S. borders. A large fraction of illegal immigrants enter the U.S. by sea, or enter the U.S. legally and overstay their visas. More than a million of them are from Asia.
Finding and deporting unauthorized immigrants would be no easy task. Many of them would be protected and hidden by their employers and friends. That could be made a crime, too, I suppose.
I don’t see how this could be enforced without a fascist-style or Soviet-style requirement that everybody be required to carry identity papers at all times, subject to arrest if they don’t, and a system of checkpoints so that people have to frequently show their papers.