Judge Shira Scheindlin of Federal District Court spoke up for the constitutional rights of blacks and Hispanics on Wednesday by granting class-action status to a lawsuit that accuses the New York Police Department of using race as the basis for stopping and frisking hundreds of thousands of citizens a year.

The decision opens the door to potential claims by an enormous number of people who may have been illegally stopped, and any remedy would be applied citywide. In a fierce defense of the Fourth Amendment, which guarantees freedom from unreasonable search and seizure, Judge Scheindlin was profoundly critical of the police program. The city’s arguments, she wrote, “do not withstand the overwhelming evidence that there, in fact, exists a centralized stop-and-frisk program that has led to thousands of unlawful stops.” She allowed the class-action status because “the vast majority of New Yorkers who are unlawfully stopped will never bring suit to vindicate their rights.”

Instead of fighting the suit, brought by the Center for Constitutional Rights, the city should be trying to settle this case and working immediately to reform a policy that violates rights and undermines trust in the police.

The stop-and-frisk program dates to the 1990s, when the police department adopted a “zero tolerance” approach to policing and began bearing down on minor crime as a way of preventing more serious crimes. Despite the city’s claims, there is no proof that this approach, by itself, reduced crime in New York because crime has fallen in many cities that do not follow New York’s lead.