YOU'VE heard of stop and frisk, the highly controversial and often unconstitutionally applied tactic wherein police search people without evidence of wrongdoing. The Pennsylvania Legislature is now considering another category of unreasonable search and seizure: stop and swab.

A bill pending in the House would allow police to collect DNA evidence from people who are arrested for felonies and certain misdemeanors by swabbing their cheeks when they're booked. It expands current law, which allows DNA evidence to be collected only after people are convicted of certain crimes. So much for the concept of innocent until proven guilty.

Stop and swab won't apply as indiscriminately as stop and frisk, and won't go into effect until after an arrest is made. But those booked for crimes they didn't commit will endure this breach of privacy nonetheless.

Not to mention that the bill requires the DNA evidence to become part of state and FBI databases. If the case is dismissed or there's an acquittal, the state will purge the record, but guess whose responsibility it will be to ensure that the DNA evidence is expunged from the FBI files: the person who's innocent.

The burden is not only an imposition, it also has uncertain results: Since when can bureaucracies be trusted to operate flawlessly or guard their databases from unauthorized use?

The sponsor of the legislation, Senate Majority Leader Dominic Pileggi, R-Delaware County, said that the legislation would help law enforcement by identifying suspects whose DNA is linked to previous unsolved crimes. Pileggi introduced a similar bill last year that failed. He reintroduced an amended version this year, bolstered by a ruling in June by the U.S. Supreme Court upholding a similar Maryland law.

Although the proposed legislation potentially could be ruled constitutional under the U.S. Supreme Court's guidelines, the American Civil Liberties Union of Pennsylvania, which is opposed to the bill, notes that Pennsylvania's top court has applied a stricter standard of unreasonable search and seizure. Pileggi's bill, if passed, could certainly fail to pass muster there.

And, although you'd expect the ACLU to oppose what it's called "warrantless searches of a person's body," consider these words from what would seem an unlikely source: Justice Antonin Scalia, who was joined by three of the top court's liberals in his dissenting opinion to the June ruling upholding Maryland's law:

"This Act manages to burden uniquely the sole group for whom the Fourth Amendment's protections ought to be most jealously guarded: people who are innocent of the State's accusations . . . Solving unsolved crimes is a noble objective, but it occupies a lower place . . . than the protection of our people from suspicionless law-enforcement searches. The Fourth Amendment must prevail."

Pileggi's bill passed the state Senate and was approved by the House Judiciary Committee. It's now before the House, to whom we say: Stop and frisk is bad enough - don't make matters worse with stop and swab. Vote the bill down.