IT'S CLEAR that the folks who drafted the city of Alexandria's new anti-loitering law went to great lengths to craft an ordinance that could withstand the inevitable constitutional challenge. What they have produced is a law so replete with caveats, stipulations and ifs-ands-and-buts that it is . . . well, ridiculous. And, yes, they are being sued by civil libertarians anyway. Perhaps that is the final lesson of this exercise: that anti-loitering laws are so difficult to construct precisely because they cannot be enforced in a fair manner and really have no place in a determined law enforcement effort designed to combat the scourge of illicit drug dealing.

The ordinance says that Alexandria police can charge a person with a misdemeanor loitering violation if that person remains in the same location for at least 15 minutes, makes face-to-face contact with at least two other people during the same time span and exchanges money or small objects with those people. That, believe it or not, is the simple version.

The police must also be sure the person in question is still within 750 feet of the spot in which he was originally observed. Step over that imaginary boundary, and the police have to start their stopwatches all over again. Next, each "contact" can last no more than two minutes, or police can't make a move. This means the officer needs at least two stopwatches or a fancy one with dual timers. The police also must watch for actions or movements consistent with an exchange of money or other small objects. There's more.

The folks being observed must also display actions or movements consistent with an effort to conceal money or an object that has been exchanged or that appears to have been exchanged. We assume this means that the police can't arrest anyone for loitering under these terms if the person makes no effort to conceal what he's doing. Finally, before police can take action under this new law, the whole face-to-face contact between these individuals must end shortly after the completion of the apparent exchange. If these two hypothetical individuals simply stand around and chew the fat for a few minutes after their "exchange," they can't be touched.

Perhaps this last fact will tell you all you need to know about the value of this law, which has been on the books since April. As of noon yesterday, no arrests had been made. "We haven't been able to find any case that meets all of the criteria," says the head of the Alexandria police narcotics division. No kidding.