See the open letter on immigration reform from economists and other social scientists at Marginal Revolution. There is still a debate on the national welfare effects of increased immigration, based on empirical work by Borjas versus that by Card. On the other hand, in at least some respects, from a welfare standpoint, free movement of workers is not very different from cross-border trade in services or trade in some types of goods. There is wide agreement that free movement of workers could bring great aggregate welfare gains. There is also wide agreement that temporary movement is a little less ambiguous in its effects, as it has less potential than permanent movement for adverse effects on the sending state. So we would expect some incentives to move forward on GATS Mode 4 . . . .