A federal judge Wednesday questioned why he should halt the District of Columbia police department's vehicle checkpoint program, which has not been reinstated since it prompted a firestorm of criticism from civil liberties groups.

"Where is the irreparable harm ... if we don't know when the program might be reinstated in the future?" U.S. District Judge Richard Leon asked during a hearing in which attorneys sought a preliminary injunction against the initiative.

The Partnership for Civil Justice filed a lawsuit in June on behalf of four residents who were stopped at checkpoints in Washington's Trinidad neighborhood. The initiative was set up at random hours over six days beginning June 7 after a spike in violence in the northeast section of the city.

Mara Verheyden-Hilliard, an attorney with the civil liberties group, told Leon it was "flagrantly unconstitutional" for police to check motorists' ID and prevent some from entering the area.

She said the court should act before the city decides to set up similar checkpoints in other neighborhoods.

The city, however, argued the initiative was justified by a "grave public concern," and that it was narrowly tailored to prevent outsiders from driving into the neighborhood, shooting at residents, and then fleeing.

At Wednesday's hearing, the judge expressed reservations about granting an injunction while he weighs the constitutional merits of the anti-crime initiative. He said such as action is used only to provide "extraordinary relief."

"At this point, it's conjecture as to whether police will set up the program in the future," Leon said. Though the judge stopped short of issuing a ruling, he said it might be more appropriate to consider an injunction if police announce plans for more checkpoints.

Police Chief Cathy Lanier has said the checkpoints were a success and told the D.C. Council that she will likely use them again in areas that see a surge in violence.

Reaction to the initiative has been mixed.

Some D.C. residents have argued that dramatic action was needed after a particularly violent weekend in which eight people were killed — most in the police district where the checkpoints were carried out. Others said the checkpoints were an overreaction that inconvenienced law-abiding citizens.

Thomas Koger, an attorney representing the city, said Wednesday that police turned away 48 of the more than 950 vehicles that tried to pass through the Trinidad checkpoints. One person was arrested for driving with alcohol.