I agree with Becker that the problem of illegal immigration is intractable, mainly for political reasons. On the one hand, illegal immigrants take some jobs that would otherwise go to Americans and, more important, by increasing the supply of labor lower average wages, at least in labor markets in which the illegal immigrants are concentrated. On the other hand, by increasing the labor supply they lower labor costs and hence product and service prices, to the benefit of consumers. Also, though they avoid some taxes and receive some taxpayer-supported benefits, they probably receive fewer benefits than they confer in the taxes they do pay. They do increase congestion, which is a negative externality, but probably not by much; it is doubtful that the illegal-immigrant population exceeds 3 or 4 percent of the nation's total. I do not think they contribute disproportionately to crime, except of course criminal violations of the immigration laws.
I am inclined to think that, on balance, the problem of illegal immigration is not one of the nation‚Äôs major problems, though it may become so if the illegal-immigrant population grows significantly. I share Becker's skepticism that much can be done about the problem, but some things can be done, though the aggregate effect may be minor:
1. Children born in the United States (unless their parents are foreign diplomatic personnel) are automatically entitled to U.S. citizenship. This rule operates as an inducement to illegal immigration, because immigrants often wish to confer the boon of U.S. citizenship on their children born here, and also believe that if their children are citizens this will make it less likely that they (the parents) will be deported. The rule is thought by many legal experts to be grounded in the Constitution, but this arguably is incorrect; and if it is correct, the Constitution could be amended to change the rule.
2. Border control has traditionally focused on arresting people caught sneaking across, and the Border Patrol based their requests for congressional funding on the number arrested. Since only a fraction of the illegal border crossers are arrested, and since when arrested they are returned to Mexico where they can try again until they finally elude arrest, this is a highly inefficient method of blocking illegal immigration. It would be better through a combination of electrical fences, electronic sensors, and stationing border patrol personnel right along the border, to prevent the entry of illegal immigrants in the first place. Arrest without punishment but merely return to Mexico is neither preventive nor deterrent.
3. A national biometric identity card, required of all U.S. citizens and issued only upon convincing proof of citizenship, would reduce the incentive for illegal immigration by increasing the likelihood of an illegal immigrant's being caught and deported.
The fact that these measures would merely slow, and not stop, illegal immigration does not strike me as cause for regret. It is not at all clear that illegal immigration is on balance a bad thing for the nation. The only real concern is that if it continues at its present rate (which Becker estimates at 500,000 a year) we will soon reach a point at which the net benefits turn negative. We can postpone arriving at that point by adopting the modest measures suggested above.