I just discovered this great old (2000) piece by Alex Tabarrok on immigration.  Highlights:

As far as
wages are concerned the only difference between immigration and birth is
that birth takes longer. When your neighbor has a child it as
equivalent to a worker entering the country 18 years in the future. The
wage argument against immigration thus also suggests that we should have
prevented the parents of the baby-boomers from having children.


now look at the immorality of immigration restrictions from other moral
perspectives. I will consider four sorts of moral theory–utilitarianism
which says that what is moral is to increase total happiness,
contemporary liberalism which says that redistribution of wealth from
the rich to the poor is moral to increase equality, John Rawls’s
analytical liberalism which says that something is moral if it would be
agreed to behind a veil of ignorance and finally I will briefly examine
Christianity’s perspective on immigration. Each of these moral theories
strongly supports open immigration and opposes restrictions on

Let’s begin with utilitarianism. It’s easy to see that immigrants
are benefited more from coming to America than natives are harmed. An
immigrant from Nazi Germany or contemporary India, China, Ethiopia or
Mexico is leaving a situation which may range anywhere from death in a
prison camp, to death by starvation and back breaking labor to misery
and death at an early age due to abject poverty. Even the poorest
Americans live in better conditions than the typical Ethiopian or
Chinese. On Utilitarian grounds, therefore, immigration is to be
applauded because it increases total world happiness.

Contemporary liberalism or any ideology which asserts the
importance of redistributing wealth from the rich to the poor would
certainly favor open borders. Immigrants are, in general, much poorer
than natives. Thus, even if natives are hurt by immigration they are
hurt much less than by what the immigrants gain. Alternatively stated if
you are in favor of any form of the welfare state then you should also
favor open borders…

What about contractarianism and Rawls’s veil of ignorance? The
basic contractarian argument is that something is just if everyone would
agree to it if they did not know information about themselves which
might bias their decisions–information say about their wealth, race, or
sex. To see the relevance, imagine that you did not know which country
you would be born into. Would you be in favor of open or closed borders?
There is some possibility that you might be born an American in which
case we are assuming that you will be harmed by immigration and
therefore will be against open borders. On the other hand there is a
much greater probability that you will leave in a poor and perhaps
dictatorial country in which case you will favor open borders. Moreover,
not only is the probability higher that you will be the sort of person
who favors open borders but the gain from open borders when you find
yourself living in desperately poor country is much greater than the
loss should you find yourself living in a rich country…

Catholic Social thought is clear on the issue of emigration and
immigration. Pope John Paul II, for example, says in Laborem Exercens,

“Man has the right to leave his native land … in order to seek
better conditions of life in another country.” Pope John Paul II,
Laborem Exercens

More generally, the ethic of kindness to strangers runs throughout Christianity especially in the New Testament.

In Luke, a lawyer challenges Jesus, “I know that to inherit eternal
life I must love they neighbor as myself,” he says but “who is my
neighbor?”. Jesus, then replies with the parable of the Good Samaritan,
the foreigner who stops to help the injured native even when his
countrymen pass him by. Neighbors are not just the people who live next

Perhaps most explicitly, Matthew 25:35 tells us that at the great
judgment “When the Son of Man comes in his glory, and all the angels
with him” the people of the world will be separated and those on the
Lord’s right hand will be told “Come you that are blessed by my father,
inherit the Kingdom prepared for you from the foundation of the world;
for I was hungry and you gave me food, I was thirsty and you gave me
something to drink, [and] I was a stranger and you welcomed me…”

Today the immigrant is like the “stranger” in whom Jesus asks to be
recognized. To welcome him and to show him solidarity is thus a duty of
hospitality and a fidelity to Christian identity. (Paraphrase of Pope
John Paul II).

Tyler Cowen often says that Alex is the Carow Hall professor most likely to be correct.  Though I’m tempted to insist, “No, that’s me,” there’s no one else I’d rather lose to.