It's hardly surprising that residents of Southwest Baltimore are gratified by the new attention they're getting from police and municipal officials. Carrollton Ridge was the site of a shooting this summer that left a 5-year-old girl critically injured, and Mill Hill was the scene of a fatal shooting a few weeks later. Both communities have suffered from crime and neglect of basic services. So it's to be expected residents there might view the city's recent decision to flood the area with uniformed patrol officers, fire inspectors and sanitation and housing department workers as a sign things may finally be turning around.

Yet the most visible police tactic at the moment is setting up barriers to redirect the traffic of people entering and leaving the area. Police defend the practice as a way of preventing drug dealers and other violent criminals from operating in the community. They say such "Safe Zones" help officers get to know residents and determine who belongs there and who doesn't.

That may be true, but civil liberties groups say the barriers may still be on shaky legal ground. This summer a three-judge panel of the U.S. Court of Appeals for the District of Columbia ruled that checkpoints set up by police to stop and question motorists entering a crime-ridden neighborhood there may have violated the Constitution's 4th Amendment ban on unreasonable searches and seizures. In that case, the court acknowledged that some checkpoints set up for specific purposes - such as apprehending drunk or unlicensed drivers - are permissible. But a mere "general interest in crime control" doesn't justify erecting checkpoint barriers.

Other courts across the country have raised similar objections, and at this point it's not clear whether the Baltimore's use of the barriers would pass constitutional muster, even though city officials say officers are not routinely stopping and questioning people. Moreover, attorneys for the plaintiffs in Washington who sued to bar checkpoints argued the barricades weren't even effective in reducing crime. Murders in the neighborhood where the checkpoints were set up dropped while they were in effect, but homicides in some other parts of the city nearly doubled over the same period.

The best thing about the city's drive to crack down on violent crime in these areas is the recognition that police are just one part of the solution and that real progress depends of meeting the needs of troubled neighborhoods on many different levels. Enforcing fire and housing code regulations, clearing blighted areas and collecting the garbage are as vital to cleaning up an area as more police, and in some cases they may even have a more long-lasting effect. Baltimore could certainly use even more social workers, drug treatment counselors and health and recreation officials in its most troubled neighborhoods.

But citizens shouldn't have to trade their civil liberties for security. The potential for abuse in police checkpoints is obvious, even though many citizens are for the moment content with the intrusion. But one can reasonably question whether setting up checkpoints and barricades at the entrance to communities is a reasonable, necessary or even particularly effective way of reducing crime. If, despite the courts' misgivings, police in Baltimore still believe that it is, they owe it to the public to explain why.