Dylan Matthews writes: “What would you think about a law that said that blacks couldn’t get a job without the government’s permission, or women couldn’t get a job without the government’s permission, or gays or Christians or anyone else?” George Mason economist Bryan Caplan asks. It’s a pretty easy question. Obviously, such a law is discriminatory on its face, serves no rational purpose, and is unacceptable in a liberal democracy. But Caplan continues: “So why, exactly, is it that people who are born on the wrong side of the border have to get government permission just to get a job?”

This is Caplan’s elevator pitch for open borders, an idea that for years was treated as deeply unserious, as an extreme straw man that nativists could beat up in the course of resisting more modest efforts to help immigrants. It had its defenders — philosopher Joseph Carens primary among them — but they were relatively lonely voices.

But in recent years, a small but devoted group of advocates have succeeded in turning open borders from a dirty word to a real movement with strong arguments backing it up. The team at OpenBorders.info — Vipul Naik, John Lee, Nathan Smith, Paul Crider — has led the charge, as Shaun Raviv wrote in an excellent profile of the group in the Atlantic. The University of Colorado’s Michael Huemer honed Carens’ moral case, while the Center for Global Development’s Michael Clemens has been hugely influential in arguing that we’re leaving trillions in potential economic growth on the table by enforcing border restrictions.

But few have been as prolific and forceful in their advocacy for the idea as Caplan. “The upside of open borders,” he once wrote, “would be the rapid elimination of absolute poverty on earth.” He is relentless at rebutting objections. It would take jobs away from native-born workers? It’d hurt growth in poor countries as more and more people leave? It’d leave us vulnerable to crime? No, no, and no. [Continue reading…]