IF MARYLAND voters are compelled to use electronic voting machines as set up by state officials, their votes on the touch-screens will be touched and gone -- never to be recounted usefully if the system crashes, hackers attack, well-meaning programmers mess up or glitches arise. Such is the unnecessary risk that Maryland is running. Opponents of this vanishing-vote system have been in court this week seeking a preliminary injunction, asking that the state be required to equip machines with printers that would make a paper copy of each ballot. On the opening day of a three-day hearing before Anne Arundel County Circuit Judge Joseph P. Manck, the plaintiffs argued that the machines to be used in Maryland "are uniquely insecure and vulnerable to outside attack" and that changes can and must be made before votes are cast in November.

Why take a risk that could upset any contest -- the presidential race included -- with no sure way of knowing what votes were counted or for whom? Experiences elsewhere in the United States should give voters pause. As reported Sunday by The Post's Dan Keating, the votes of 678 voters in Rio Arriba County, N.M., were never recorded by the electronic machines in use there four years ago. Vice President Al Gore won the state by 366 votes. Even if all the missing votes had been for George W. Bush and given him the state's five electoral votes, it would not have changed the outcome of the presidential race; still, the foul-up showed what could happen in a tight vote if the machines are not correctly programmed -- and how little could be done about it afterward.

At the Maryland hearing, Assistant Attorney General Michael D. Berman said the potential problems cited in the lawsuit by TrueVoteMD are based on "theoretical security vulnerabilities" that have not materialized in previous elections. But should we wait for an ugly surprise before taking a fundamental precaution? Maryland officials have spent too much time already resisting changes that can and should be made. For the record -- the record that they may not have when election troubles arise -- the integrity of the process should be protected.