The answer provided is less economic than political. Yes, libertarian thought posits all government action beyond security and justice to be superfluous and destructive of liberty and property. So, the arguments presented is not that there is any economic difference between intra- and international trade, rather political considerations distort markets and can artificially create win-lose propositions where none should exist. So Prof Rodrik assumes political reality as set and unchangeable, therefore artificial political restrictions on voluntary, peaceful exchange are justifiable in the eyes of those imposing them. Political fatalism masquerading as economic theory...