Paul Krugman on immigration

On TimesSelect:

I’m instinctively, emotionally pro-immigration. But a review of
serious, nonpartisan research reveals some uncomfortable facts about
the economics of modern immigration, and immigration from Mexico in
particular. If people like me are going to respond effectively to
anti-immigrant demagogues, we have to acknowledge those facts.

First,
the net benefits to the U.S. economy from immigration, aside from the
large gains to the immigrants themselves, are small. Realistic
estimates suggest that immigration since 1980 has raised the total
income of native-born Americans by no more than a fraction of 1
percent.

Brad DeLong reproduces more text, along with cosmopolitan commentary.  I would also stress the benefits of a relatively free and prosperous Mexico on our southern border.  The path is not without further bumps, but Mexico has turned the corner.  Without high immigration, remittances (second biggest "export," I believe), and the spread of liberal democratic ideas, Mexico probably would have been much worse off.  In the long run this will prove hugely beneficial to the United States, and of course to the rest of Latin America as well.

Tyrone wants to ask the cosmopolitan the embarrassing question: "At some margin immigration slots are scarce.  Why are we wasting them on relatively wealthy Mexicans?"

National self-interest may provide a partial answer.