The first issue is to pin down what we mean by open borders.
Land use restrictions are often a more important ""immigration
policy" than border control per se. It is not just how many people get
in at what cost, but who can afford to live here. This includes zoning laws,
restrictions on the number of people allowed to live in an apartment,
policies toward "squatters," and rules for the homesteading of public
property. So by "open borders" I mean also liberal land use policies;
nominally open borders would matter far less if unskilled laborers
couldn’t also afford to live in the U.S. (Note to anti-immigration
types: you are focusing too much on the ease of crossing the border
and not enough on the costs of living here. How much the best
immigration restrictions involve land use policy or border policy is a
curiously underexplored question.)
If both the border and land use were free, markets would be very
powerful in organizing mass migration. Consider Hyderabad. Many of
the very poor live either at or right next to garbage dumps. They live
in tents or ramshackle lean-tos. Their jobs often involve scavenging
the garbage dump for potentially useful scraps. Why do they live
there? Do they like the short commute? Is it because they love the
Indian culture one finds right next to the garbage dump? No, no, and
no. They live there because they will put up with almost anything to
have a chance of survival.
How many of these people would book passage on a slow ship to
Baltimore, with the hope of living in a richer garbage dump? The ship
would serve cheap rice and lentils, make them sew garments while sailing, and collect further payment five years after
arrival, tagging them with GPS if need be or "monitoring" relatives
back home. Or perhaps the Indian government would pay their way.
How about the nine or so million Haitians — almost all living in
extreme poverty — who face a much shorter and cheaper boat trip?
I can imagine the U.S. staying a high-quality capitalist democracy
with some percentage of the population living in garbage dumps and
shantytowns. While I think we are underinvesting in shantytowns, the permissible percentage is not very high and almost certainly falls short of fifteen percent. (Btw,
there is much complaining about the Mexicans, but in fact we share a
long land border with a relatively wealthy third world country; this is
That is why I do not favor unlimited immigration. To the extent
that nominally "open borders" would be tolerable, it is because we already impose
implicit immigration restrictions through land use policies.
That all said, I will reiterate my view that we could take in many
more immigrants than we are doing now, both skilled and unskilled.