NEXT TIME you call your beloved on your fancy new cordless phone, better be careful.

And when you want to call your business partner from the car to discuss the sealed bid you just submitted, don't do it. In either case someone may be listening, and the eavesdropper probably wouldn't be breaking the law. He might not even know you, but may have bought a "scanner" just to listen in on conversations for the fun of it. One manufacturer urges busybodies to buy simply because private conversations "offer more real-life intrigue than most soap operas."

You may have thought that the law forbids telephone wiretaps and that even law enforcement agencies can't tap without a court order. That certainly was the intent of Congress when the Omnibus Crime Control and Safe Streets Act was passed in 1968. Both the trouble and the loophole are the result of technology's outstripping the law in the last 20 years. Phones that are essentially radio transmitters, such as cordless models and car phones, are not protected by the old law. Neither are electronic mail, computer conferences, satellite communications systems, paging devices or lightweight, compact television cameras for video surveillance.

What's to be done? Even the courts aren't sure, and at least one federal appeals judge has urged Congress to provide some guidance. Policy on electronic surveillance must balance two interests: the government's responsibility to investigate and prosecute wrongdoers, and the citizen's right to maintain civil liberties protections. These are balanced in the laws that cover wire communications, and surely some of those restrictions should be applied to the new technologies.

Identical bills on this subject have been introduced by Rep. Robert Kastenmeier (D-Wisc.) and Sen. Patrick Leahy (D-Vt.). Both bills have been the subject of hearings and are expected to be marked up this spring. The bills would extend the protection against interception of voice transmissions to almost all electronic communications. Exceptions are carved out for systems -- ship-to-shore radio, ham radio, police and fire communications -- where public access is expected. The bills also provide protection against the interruption, alteration or disclosure of information in electronic communications systems. These are comprehensive measures that propose many changes in existing law, and the Justice Department is working with the authors to iron out differences, particularly over those parts that affect investigative surveillance. But the law must be clarified, because unanticipated loopholes enable a serious invasion of prizacy. They should be closed, and soon.