It's hard to understand the controversy over a new state rule that puts non-citizens' visa-expiration dates on their drivers' licenses. All this relatively minor rule does is allow police to spot people who are in the country illegally. Why would a tool for police to spot lawbreakers cause a controversy?

Somehow, it is. Lawyers argued yesterday that the rule, along with a couple other drivers-license changes, are unconstitutional. They say having a date stamped in the corner of an I.D. is discriminatory somehow.

The rule was enacted as a security measure. Knowing that some of the Sept. 11 hijackers were in this country on expired visas, and were even stopped and let go by police before the terrorist attacks, the Department of Public Safety made the change last year. With security concerns so important, it was a prudent step that, at the very least, might catch a few people for immigration violations.

One argument against the rule, however, is that it unfairly brands non-citizens and calls special police attention to them. But the fact of the matter is that police will only pay special attention to them if their visas are expired, in which case they brought it on themselves by being in this country improperly.

It's an unfortunate side-effect if a few people feel uncomfortable about having a visa-expiration date on their drivers' licenses. But most Americans have had to deal with some minor inconveniences since Sept. 11, 2001. The need for security is too great and the arguments against this rule are too weak to scrap the idea.