In a conversation with Tyler Cowen, Romer says,

I think we should talk about a trilemma for migration, which is three things, and we can only have two out of the three. You think of the liberal democracies — what would we like as a response for large numbers of people who need to go someplace? If it was some political jurisdictions, one of the things we want is local democratic accountability for the officials in the government. The second would be equal treatment under the law. And the third is, in this jurisdiction, the ability to absorb large numbers of migrants, potentially numbers that are bigger than the existing population.

Picture one of these places when there’s a million people there, but you’d like it to be able to accept another 9 million. All three of those things are things that most people would support, and you can’t have all three. So, the two we pick in most existing jurisdictions — we just don’t allow large-scale migration, and you can see some logic to that.

His preferred solution is to suspend local democracy for a while, until the immigrants are absorbed. I think of this as adding Syrian refugees to Germany but, instead of letting the Syrian refugees vote in a different set of rules, letting the EU run things there.

It’s a very unfamiliar approach, and it has features that are unattractive. But the thing to realize is, we just don’t have an answer at all if we’re facing this kind of very large-scale crisis of migration.

First,

As a property owner, your share of public goods is not yours to dispense as you please, permanently and in perpetuity to their birthright-citizen posterity, to non-citizens.

As a property owner, you pay property taxes and income taxes on the rent that you charge. Your illegal immigrant tenant pays gasoline taxes, sales taxes, and (perhaps) payroll taxes. It is not clear that the immigrant is less morally entitled than anyone else to whatever public goods that immigrant receives.

Second,

If a student illegally admitted himself to Harvard, enrolled in classes, followed all the normal rules, completed assignments, took tests, and paid his tuition like expected, would it be immoral to kick him out? Is it immoral for Harvard to block the student from getting legal admission by rejecting his application?

In fact, you don’t even have to pay tuition to tresspass on classes, and my guess is that if you submit a test it will be graded. But you won’t get the Harvard degree without coming in through the front door via the admissions process. Bryan Caplan uses this example to show that the value of college must be mostly signaling; if it were the education itself that had value, then we would see more people would obtain the education by trespassing.

As for Harvard blocking the student from getting admission, that is because Harvard sees its slots as a scarce resource. In theory, these could be rationed entirely on the basis of price, with slots going to the highest bidders. In practice, Harvard rations these slots through the admissions process. It is free to do so.

Illegal immigrants who occupy housing are using scarce land resources. But those resources are being rationed on the basis of price.

Arguing against allowing illegal immigrants means arguing in favor of some non-price rationing of land resources. Moreover, you are not giving the landlord the right to choose whether and how to ration by non-price criteria. Instead, you are having the government set the criteria.

I am not trying to refute the case for enforcing immigration laws. I am just trying to say that the analogy between kicking out an immigrant and throwing someone off of your personal private property is not really appropriate.

In response to a comment, here is some textbook international economics.

1. A 10 percent tariff has the same effect on the relative cost of imports as a 10 percent depreciation of our currency.

2. The macroeconomic theory of the trade balance is that it is determined by the difference between domestic saving and domestic investment:

(private saving minus private investment) plus (government surplus) = (trade surplus)

3. If a tariff does not change anything on the left-hand side, it cannot change anything on the right-hand side. That requires an offsetting appreciation of the exchange rate.

4. Thus, textbook international economics predicts that a tariff (or a tariff combined with an export subsidy) will have no effect on the trade balance, but instead it will cause the domestic currency to strengthen.

5. The border-adjustment tax is analyzed as if it were an import tariff and an export subsidy. Ergo, its effect is on the exchange rate, not on the trade balance.

I wrote,

On the topic of international trade, the views of economists tend to differ from those of the general public. There are three principal differences. First, many noneconomists believe that it is more advantageous to trade with other members of one’s nation or ethnic group than with outsiders. Economists see all forms of trade as equally advantageous. Second, many noneconomists believe that exports are better than imports for the economy. Economists believe that all trade is good for the economy. Third, many noneconomists believe that a country’s balance of trade is governed by the “competitiveness” of its wage rates, tariffs, and other factors. Economists believe that the balance of trade is governed by many factors, including the above, but also including differences in national saving and investment.

The noneconomic views of trade all seem to stem from a common root: the tendency for human beings to emphasize tribal rivalries. For most people, viewing trade as a rivalry is as instinctive as rooting for their national team in Olympic basketball.

To economists, Olympic basketball is not an appropriate analogy for international trade. Instead, we see international trade as analogous to a production technique. Opening up to trade is equivalent to adopting a more efficient technology.

That was for the Concise Encyclopedia of Economics.