In France and many other countries, citizens and travelers alike are required to have their identification on their person at all times. In the U.S., however, that is not the case. We live in a society that prizes the right to privacy, of which anonymity is a facet.

This may soon change. This Term, in the case of Hiibel v. Sixth Judicial District Court of Nevada, the Supreme Court will decide a case that asks the following question: Does the Constitution permit a police officer to arrest someone simply because, when stopped under reasonable suspicion, that person fails to produce identification?

The federal judicial Circuits have split on this issue. The Tenth Circuit has upheld a similar statute in Oliver v. Woods, while the Ninth Circuit has struck another down in Carey v. Nevada Gaming Control Board. The Nevada Supreme Court -- which issued the decision the Supreme Court is reviewing -- has already held that this type of arrest does not violate the Constitution.

It would be a serious mistake for the Supreme Court to agree. Because the standard for reasonable suspicion is very low, the upshot of such a decision would be to require all citizens, immigrants, and travelers in America to carry identification at all times -- and to be prepared to produce it for inspection.

Reasonable suspicion is an extremely low standard -- even lower than probable cause. In practice, it merely requires the police officer to be able to articulate some reason why he found you suspicious -- which is generally very easy to do, particularly under the vaguely defined "totality of the circumstances" test that is used.

Under the leading Supreme Court decision in Terry v. Ohio, passing by the same storefront too many times can trigger "reasonable suspicion." Under the recent Supreme Court decision Illinois v. Wardlow, it may trigger reasonable suspicion if, in a dangerous area of town, a person runs when he sees a police officer approaching. Under a case decided by the U.S. Court of Appeals for the Eleventh Circuit, United States v. Cruz, simply walking alongside the wrong acquaintance can trigger "reasonable suspicion." Racial profiling can be factor when articulating reasonable suspicion, as can the crime rate of the neighborhood you are in or the activities of people you know.

In sum, no one can be sure he or she will not trigger "reasonable suspicion," in the eyes of a police officer (and in the eyes of the law). Suppose that the Supreme Court affirms the decision in Hiibel that "reasonable suspicion" plus the failure to produce identification can constitutionally lead to arrest. If so, all Americans will be well-advised to carry I.D. at all times.

Otherwise, they may risk unwittingly triggering "reasonable suspicion," and thus being arrested merely, in effect, for failure to produce identification.

Being required to carry I.D. may not seem to be a problem. Many people carry identification with them at all times already -- carrying a driver's license in their purse or wallet, or if they are younger, a student I.D. card. For them, having to show I.D. would be only a slight inconvenience.

Moreover, in this age of the "war on terrorism," some may consider it to be a good idea for the police to be able to "card" anyone on the street about whom they have a hunch. There are those who believe that the inconvenience is somehow balanced by an increase in the safety and effectiveness of the police.

If we do not guard our privacy and the option of our anonymity, it may be taken away from us. If convenience and terror convince us that it costs little to discard the right to privacy in our own names, we will have lost something. Furthermore, its true value may not yet be apparent.

After all, most people don't bear arms, or find themselves in a situation where they might need a trial by jury, or bother to speak out to the full extent that the First Amendment makes possible. But when they need the ability to do any of these things, they are glad of having these rights to call upon. Rights do not become less valuable simply because they are not widely used. They must remain, dormant and undiminished, until the day when we find that suddenly they are needed

There may come a time when privacy retreats still further, and we find that in a rapidly shrinking world everybody knows our names -- whether we like it or not. By then, it will be too late to preserve our right to anonymity. We must carefully guard that right now. Let us hope, then, that the Supreme Court, in Hiibel, holds that Americans need not carry identification in order to avoid arrest.