NEW YORK (AFP) - A federal judge upended a cornerstone of New York policing on Monday, declaring the city's controversial stop-and-frisk policy a violation of the US constitution that unfairly targeted blacks and Hispanics.
In a 198-page ruling, Judge Shira Scheindlin said police randomly stopping individuals on the street and subjecting them to searches violates the Fourth Amendment's protection against unreasonable search and seizure.
It also runs afoul of the Fourteenth Amendment's guarantee of equal protection under the law, said Scheindlin, who stressed how young black and Hispanic males were most likely to be targeted.
"The evidence at trial revealed that the New York Police Department (NYPD) has an unwritten policy of targeting 'the right people' for stops," the judge said.
"In practice, the policy encourages the targeting of young black and Hispanic men based on their prevalence in local crime complaints. This is a form of racial profiling."
Mayor Michael Bloomberg said his administration would appeal the ruling, telling reporters that stop-and-search was a "vital deterrent" that had taken 8,000 guns off the street over a decade.
"There is no question that stop, question and frisk has saved countless lives," he said.
Judge Scheindlin, a US District Court judge, refrained from ordering a total halt to stop-and-frisk.
But in a move unprecedented in New York police history, she ordered the appointment of an independent monitor to ensure that such searches are carried out "in accordance with the Constitution."
Mr Bloomberg bristled at that idea, saying it was tantamount to putting the NYPD and its nearly 35,000 uniformed personnel "into receivership." Stop-and-frisk has been a centrepiece of New York's efforts to bring criminality to heel after the drug-fueled violence of the 1980s and early 1990s.
Of the 4.4 million cases between January 2004 and January 2012 in which New York police briefly detained individuals on suspicion of criminal involvement, 52 per cent involved blacks and 31 per cent Hispanics. Only 10 per cent involved whites.
"The city and its highest officials believe that blacks and Hispanics should be stopped at the same rate as their proportion of the local criminal suspect population," Scheindlin said.
"But this reasoning is flawed because the stopped population is overwhelmingly innocent - not criminal." The ruling was a victory for the Center for Constitutional Rights, a New York group that filed a class-action lawsuit seeking federal oversight of stop-and-frisk.
"Today is a victory for all New Yorkers," it said in a statement.
"After more than five million stops conducted under the current administration, hundreds of thousands of them illegal and discriminatory, the New York Police Department has finally been held accountable," it added.
"It is time for the city to stop denying the problem and work with the community to fix it." Mr Bloomberg, completing his third and final term as mayor, said stop-and-frisk was one of the crime-fighting tools that had made New York "the safest big city in America." From an average of six murders a day in 1990, the city of 8.245 million now sees less than one homicide per day.
"If murder rates over the last 11 years had been the same as the previous 11 years, more than 7,300 people who today are alive would be dead," the mayor said.
And most of them, he added, would be young black and Hispanic males.
Looking forward to the appeals process, Mr Bloomberg said the city would argue that it did not get a fair hearing from judge Scheindlin, who he said had given "strategic advice to the plaintiffs" prior to hearing the case.
"We will also be pointing out to the appeals court that Supreme Court precedents (favouring stop-and-frisk) were largely ignored in this decision," he added.