Here we are again with the federal government partly shut down, for who knows how long, over the issue of whether or not to appropriate money to build a Wall along the length of the border with Mexico. “Wall” is capitalized because that is how its proponents, from the president on down, seem to think about it. In our view, the Wall is a psychological illusion that does nothing to address the main source of immigration law violation, which is people who enter the country legally and then overstay their visas. Serious enforcement of the existing immigration laws would require an entirely different approach.

The purpose of the Wall is psychological. Bismarck once said the Americans were lucky because they were bordered on two sides by weak neighbors and the other two by fish. Americans like to think of the continental United States as a de facto island immune from the rest of the world. We inherited that outlook from the British, who felt, from Shakespeare until the Luftwaffe arrived, that what Churchill called “our famous island race” was uniquely favored by Providence because they lived on an island. September 11 was our Luftwaffe, and it is no longer possible to think of ourselves as being able to take or leave the outside world at will. Instead, it is very much here, both as foreign competition and as domestic competition from immigrant labor. Mexico and points south remain our neighbors, but they are no longer weak in their ability to affect what happens in this country.

The president and his true believers in the Wall want to make the outside world go away and make the USA an island once again. As he put it two weeks ago, if our southern border were impregnable, people from Central America would give up the idea of crossing it and stay where they belong. That vision doesn't respond to reality. According to government figures, illegal crossings of the Mexican border and smuggling by sea have declined by 90 percent since 2000. They now amount only to between one-fourth and one-third of unauthorized immigrants. The great majority of immigration law violators enter the country lawfully and overstay their visas. The present surge at the border is asylum seekers presenting themselves at ports of entry to seek legal admission. All of the concrete and barbed wire we could install won't do anything about that. Real enforcement of the immigration laws requires enforcement in depth, and enforcement in depth requires documentation.

If we were truly serious about enforcing the immigration laws, we would set up a national biometric identity system with a central database that shows citizenship or immigration status, require every citizen, green card holder, and lawful temporary visitor to register, and require that the identification be produced for employment or for any contact with any level of government. Even allowing for the inevitable forgeries, a national identity system would sieve out the great bulk of illegal aliens who enter lawfully and overstay their visas, it would make clear which legal entrants had the right to work or receive benefits, and it would make the unregistered unemployable except for cash-basis work on the margin. It would be expensive to establish, but most European countries have workable national identity documents, coupled with strict legal controls on their permitted use.

It would certainly be costly to establish a national identity system in the United States. Under current interpretations of the 10th Amendment, the federal government would have to foot the bill itself, rather than using existing state bureaucracies like the motor vehicle system. The logistics of initial registration would be daunting. Elders and low-income persons are less likely to have ready access to documents that will be needed to establish their lawful residency. What is an inconvenience to members of the middle class collecting the evidence needed to get a driver's license can be a formidable barrier to a citizen working at subsistence level, who is also less able, less trusting, and thus less likely, to take time from work to personally appear before yet another government agency to establish their claim. Without vigorous protections, the effect of non-compliance will likely have a racially disparate impact.

More importantly, the use of a national identity document would have to be stringently controlled to prevent a “show me your papers” police state. To avoid a catastrophic wave of mass deportation, implementation would have to be coupled with some kind of amnesty for otherwise law-abiding people who have been illegally present for many years. Fourth Amendment restrictions on investigatory stops would have to be complied with. And when identification is required, it will have to be demanded consistently and routinely from everyone, regardless of race or place of birth, to prevent it from being abused as merely a tool of racial profiling. But no other enforcement device responds to the reality of how people unlawfully enter the United States or why they come and stay here.

We recognize that there is and always will be substantial political opposition to the idea. Some civil libertarians will ignore the experience of Western Europe and regard it as the beginning of a slippery slope towards a centralized system of social control like the one the Chinese government is constructing. Some birthright citizens will regard it as an indignity to have to prove their right to be here. Large employers of vulnerable low-wage workers will want nothing to do with a system that could effectively hold them responsible for who they hire. Open or covert believers in immigration unrestricted as a practical matter will denounce anything that might make law enforcement anything more than a haphazard misfortune.

Members of both parties who honestly believe that the United States has the sovereign right to decide for its own interest which foreigners are privileged to come and stay here and which are not need to start thinking seriously about a national identity system as part of a comprehensive package of immigration law reform. If the advocates of stringent enforcement of the immigrant laws were truly serious, they would be willing to subject themselves and all other birthright citizens to the cost, the inconvenience, and the scrutiny involved in a comprehensive identity system. Let that debate begin.