Paul Krugman claims that liberals are divided on migration because:
Democrats are torn individually (a state I share). On one side, they favor helping those in need, which inclines them to look sympathetically on immigrants; plus they’re relatively open to a multicultural, multiracial society. I know that when I look at today’s Mexicans and Central Americans, they seem to me fundamentally the same as my grandparents seeking a better life in America.
On the other side, however, open immigration can’t coexist with a strong social safety net; if you’re going to assure health care and a decent income to everyone, you can’t make that offer global.
I don’t dispute his analysis of the politics. But I do disagree with his belief that free migration threatens the welfare state, let alone America’s threadbare social safety net, as I argued here.
As I set out at length in a paper for the Government of Sweden’s Globalisation Council, “Is Free Migration Compatible with a European-Style Welfare State?“, there is no evidence that even Sweden’s generous welfare system acts as a welfare magnet.
Consider that when Poles joined the European Union, only 3 countries allowed them to come and work freely: Sweden, with the most generous welfare state on earth; Britain, which denied Poles access to welfare benefits for the first year; and Ireland (likewise).
Guess how many Polish migrants went to Sweden? Fewer than 1% of them, and most of those to work, not claim welfare.
What’s more, migrants’ contribution to public finances is generally positive, not just because they pay more in taxes than they take in benefits and public services, but more importantly because their diversity and dynamism boosts economic growth.
In short, far from threatening the welfare state, free migration could help to pay for it.