Why I've changed my mind on open borders (reluctantly)

I used to hold a fairly standard open-borders liberal position: freedom of movement is the default, restrictions require justification. I've spent the last two years working through the counter-arguments more carefully and I no longer hold that position with confidence. The argument that moved me most isn't the cultural one (which I still find largely motivated reasoning). It's the political economy argument: there's decent evidence that rapid large-scale immigration correlates with electoral shifts toward nationalist parties that are far more harmful on a wider range of policy dimensions than any realistic immigration restriction would be. If open borders triggers responses that produce Le Pen, Meloni, and their policy packages — across healthcare, environment, and civil liberties — the welfare calculus looks different than a simple sum of migrant welfare gains. I don't think this means strict limits are right. I think it means the optimal policy is probably somewhere in the middle and the confident positions on both ends are ignoring real tradeoffs.