In the wake of the September 11 terrorist attacks have come many proposals for tightening security; some measures to that end have already been taken. Civil libertarians are troubled. They fear that concerns about national security will lead to an erosion of civil liberties. They offer historical examples of supposed overreactions to threats to national security. They treat our existing civil liberties—freedom of the press, protections of privacy and of the rights of criminal suspects, and the rest—as sacrosanct, insisting that the battle against international terrorism accommodate itself to them.
I consider this a profoundly mistaken approach to the question of balancing liberty and security. The basic mistake is the prioritizing of liberty. It is a mistake about law and a mistake about history. Let me begin with law. What we take to be our civil liberties—for example, immunity from arrest except upon probable cause to believe we've committed a crime, and from prosecution for violating a criminal statute enacted after we committed the act that violates it—were made legal rights by the Constitution and other enactments. The other enactments can be changed relatively easily, by amendatory legislation. Amending the Constitution is much more difficult. In recognition of this the Framers left most of the constitutional provisions that confer rights pretty vague. The courts have made them definite.
Concretely, the scope of these rights has been determined, through an interaction of constitutional text and subsequent judicial interpretation, by a weighing of competing interests. I'll call them the public-safety interest and the liberty interest. Neither, in my view, has priority. They are both important, and their relative importance changes from time to time and from situation to situation. The safer the nation feels, the more weight judges will be willing to give to the liberty interest. The greater the threat that an activity poses to the nation's safety, the stronger will the grounds seem for seeking to repress that activity, even at some cost to liberty. This fluid approach is only common sense. Supreme Court Justice Robert Jackson gave it vivid expression many years ago when he said, in dissenting from a free-speech decision he thought doctrinaire, that the Bill of Rights should not be made into a suicide pact. It was not intended to be such, and the present contours of the rights that it confers, having been shaped far more by judicial interpretation than by the literal text (which doesn't define such critical terms as "due process of law" and "unreasonable" arrests and searches), are alterable in response to changing threats to national security.
If it is true, therefore, as it appears to be at this writing, that the events of September 11 have revealed the United States to be in much greater jeopardy from international terrorism than had previously been believed—have revealed it to be threatened by a diffuse, shadowy enemy that must be fought with police measures as well as military force—it stands to reason that our civil liberties will be curtailed. They should be curtailed, to the extent that the benefits in greater security outweigh the costs in reduced liberty. All that can reasonably be asked of the responsible legislative and judicial officials is that they weigh the costs as carefully as the benefits.
It will be argued that the lesson of history is that officials habitually exaggerate dangers to the nation's security. But the lesson of history is the opposite. It is because officials have repeatedly and disastrously underestimated these dangers that our history is as violent as it is. Consider such underestimated dangers as that of secession, which led to the Civil War; of a Japanese attack on the United States, which led to the disaster at Pearl Harbor; of Soviet espionage in the 1940s, which accelerated the Soviet Union's acquisition of nuclear weapons and emboldened Stalin to encourage North Korea's invasion of South Korea; of the installation of Soviet missiles in Cuba, which precipitated the Cuban missile crisis; of political assassinations and outbreaks of urban violence in the 1960s; of the Tet Offensive of 1968; of the Iranian revolution of 1979 and the subsequent taking of American diplomats as hostages; and, for that matter, of the events of September 11.