If it's true that theory and evidence in favor of protectionism are sufficiently strong to warrant economists abandoning their conclusion that free-trade policy is generally sound, then why shouldn't economists -- led by Dani Rodrik -- also start exploring the potential benefits of intra-national protectionism? Surely a scholar not benighted with the free-trade "faith" ought to take seriously the possibility that, say, Tennesseeans could be made wealthier if their government in Nashville restricts their ability to trade with people in Kentucky, Texas, Rhode Island, and other states?
I suspect that if someone proposed to Dani Rodrik that he explore the wealth-creating potential of state-level protectionism, he would refuse. He would likely (and correctly) say that it's ridiculous on its face to suppose that such protectionism would make the people of Tennessee as a group wealthier over time.
--Don Boudreaux on the equivalence of international and intranational trade restrictions