Don Boudreaux thoughtfully discusses the putative political externalities of immigration, then ends on a pessimistic note:

I have no illusions (I really and truly do not) that anything that I
write here, or that I might write in follow-up posts or essays, will
convince my concerned friends that the greater danger to the freedom
that they cherish lies in excusing pragmatic-seeming exceptions to
freedom rather than in a principled commitment to maintain freedom…

I’m more hopeful.  I can’t persuade everyone to embrace free immigration.  But I think I can persuade Don’s concerned friends, given time.  And there’s no time to start like the present.  Here is my appeal to the concerned friends of Don Boudreaux:

1. Contrary to Don, we should be open to “pragmatic-seeming exceptions to freedom.”  But to qualify as a “pragmatic exception to freedom,” the exception has to be (a) small and (b) yield large gains with high certainty.  Restricting access to plutonium is a good example of a pragmatic exception to freedom:  There are few peaceful uses, and plutonium in the wrong hands is likely to kill millions. 

2. Restricting immigration is not a small restriction on freedom.  It deprives hundreds of millions of desperate people of the basic right to sell their labor to willing employers, causing massive global poverty.  Hard truth: immigration restrictions are genuinely more oppressive than the infamous Jim Crow laws.

3. Restricting immigration to keep immigrants from voting does not yield sharply more libertarian policies with high certainty

a. Immigrants are at worst only modestly less freedom-loving than natives.  Natives aren’t libertarians, and immigrants aren’t Stalinists.

b. It’s not clear that immigrants are less freedom-loving than natives.  Immigrants’ detractors focus on their allegiance to the Democratic Party.  But after the George W. Bush era, it’s hard to say if Democrats are more statist overall than Republicans.  Obama’s been a disaster, but how much of his agenda would have happened anyway if his Republican opponents had defeated him?

c. In any case, the low-skilled immigrants most likely to frighten Don’s concerned friends have little political influence because (a) they have low turnout and (b) democracy largely ignores low-income voters’ preferences.

d. Finally, immigrants probably reduce native support for the welfare state by undermining our group identity.  This is a standard story about why the welfare state is smaller in the U.S. than Europe: People happily vote for big government as long as the beneficiaries look like they do. 

e. By the way, immigrants are clearly more libertarian than natives on immigration policy itself.  Think about this the next time that natives complain that immigrant voters are oppressing them. 

I could talk about all the economic benefits immigrants offer to natives.  I’ve done so elsewhere.  But if you’re a concerned friend of Don Boudreaux, this is beside the point.  You may not be as absolutist as Don, but you share his presumption of human liberty.  If there isn’t a strong, clear case in favor of immigration restriction, how can you in good conscience say anything other than, “Tear down this wall”?