there is something of a tyranny of ideas in seeing the political divisions of states (primarily, national states) as being, in some way, fundamental, and in seeing them not only as practical constraints to be addressed, but as divisions of basic significance in ethics and political philosophy.

That is Amartya Sen in The Idea of Justice. It comes from a masterful slide presentation by Dani Rodrik on the economic and moral imperative for further opening. Maybe not masterful from a graphic design perspective, but for content and brevity it’s a winner.

The bottom line of his calculations: letting someone migrate to the West does so much for their wealth, at so little cost to Western workers, that we have to care about a random person inside our borders five times as much as someone on the other side to justify not letting the outsiders in.

Or we have to value whatever we think we get from closed borders (protecting the culture) so much that we’re willing to deny other human beings a path from poverty.

Here is one counterargument I seldom see: Theory and history tell us that rapid changes in economic and political power lead to conflict, some of it violent, some of it so bad the state collapses. This is a big, bad spillover that economists tend to ignore more than they should.

The West’s institutions are pretty strong, so I don’t fear collapse unless big migration came at the same time as a massive economic disaster. But I’d expect far right and nativist parties to grow in power and this could pervert politics in unfortunate ways for a few generations.

On the other hand I think there are positive spillovers too. And at worst I think this conflict counterargument is merely a case for gradual change. But not glacial, which is the current pace.

Nonetheless, read Dani’s slides for much more. It sounds like a terrific book underway.

And hat tip to Tyler Cowen.