Imagine that it is your professional duty to report a cost-benefit analysis of liberalizing immigration policy. You wouldn’t dream of producing a study that counted “men only” or “whites only,” at least not without specific, clearly stated reasons for dividing the data.
So why report cost-benefit results only for United States citizens or residents, as is sometimes done in analyses of both international trade and migration? The nation-state is a good practical institution, but it does not provide the final moral delineation of which people count and which do not. So commentators on trade and immigration should stress the cosmopolitan perspective, knowing that the practical imperatives of the nation-state will not be underrepresented in the ensuing debate.