The potential that a citizen will commit a crime or even a terrorist act is just as real as the potential that an immigrant will. No country has a monopoly on violent lawbreakers, and in no country are they nonexistent. The rule of law, and the lawful prosecution of those who commit crimes, makes a lot more sense than closing borders as a way to reduce criminality.
Terrorist acts in the United States have been committed by citizens and by immigrants, and for causes related to domestic as well as international issues. In 2000, the FBI reported no incidents of international terrorism carried out inside the United States and eight incidents of domestic terrorism, all carried out by U.S. citizens belonging to animal rights groups or environmental groups. In 2001, there were twelve incidents of domestic terrorism, one (the September 11 attacks) of international terrorism, and one (the anthraxlaced-letter incidents) of unknown origins. Environmental and animal rights groups (in this case the Earth Liberation Front and the Animal Liberation Front) were again the apparent perpetrators of several of the twelve domestic incidents, joined in 2001 by two carried out by anti-abortion activists.1
Those involved in the 9/11 attacks, which in scale dwarfed the other attacks taking place in the United States, were not citizens. However, all but four were legally in the country at the time of the attacks, having entered on tourist or student visas. A study of forty-eight “militant Islamic terrorists” who committed crimes in the United States, by the anti-immigration Center for Immigration Studies, found that thirty-six of them were in the country legally at the time they committed crimes, and seventeen were either permanent residents or naturalized citizens. Those who were not permanent residents had received visas—mostly tourist visas—to come to the country, and most of them had not violated the terms of their visas.2 Not even the highest fence or the most militarized border in the world would have kept them out. Their crimes were crimes of violence, not crimes of immigration.
It’s true that there have been in the past, and may be in the future, individuals working with international terrorist organizations who want to enter the United States. However, these are actually among the least likely people to risk arrest and death trying to cross the border illegally. It’s much more likely that members of an international organization like Al-Qaeda will, like the September 11 perpetrators, use perfectly legal channels to get into the United States.
Does this mean that we need to do better, or different, screening of those who want to enter the United States by legal means? Possibly. But the idea that screening people who cross borders is an effective way to deter terrorist attacks is also a kind of a mirage. Just as U.S. planes cross international borders to drop bombs, usually without going through any kind of immigration control process, so could the United States become the victim of international attack, regardless of its border control policies. The planes that flew into the twin towers on September 11 happened to take off in Boston … But they could just as well have taken off from some other country. Hijackers, like invaders, have proven quite able to cross borders and kill people without permission. And criminals can be born anywhere, including inside the United States. There is just no logical relationship between border security and the prevention of terrorism.
Is there, then, nothing that can be done to prevent future terrorist attacks? First, those of us who live in the United States should remember that the number of civilians killed by U.S. military attacks on other countries has far, far exceeded the number of U.S. civilians killed by attacks on the United States, or against U.S. citizens elsewhere. So curbing U.S. military aggression would probably be the most effective way to achieve a global reduction in attacks on unarmed civilians.
As far as preventing future attacks against U.S. targets, a combination of two approaches seems most likely to achieve that result. On one hand, seeking to reduce global tensions, and in particular U.S. unilateralism and aggression, could substantially reduce anti-Americanism in other countries. Second, effective police and investigative work—abiding by international law, international agreements, and the Geneva Conventions—at least offers the possibility of working toward a world ruled by law, in which criminals are prosecuted under the rule of law for the crimes they commit, and those not accused of any crime are spared the fate of becoming collateral damage.