We begin tonight with a big question about the safety of america's streets and what police say they need to keep law and order. The tactic is called stop and frisk. Today, a judge dealt a major blow,... See More
We begin tonight with a big question about the safety of america's streets and what police say they need to keep law and order. The tactic is called stop and frisk. Today, a judge dealt a major blow, saying it could open the door to racism. Tonight police are fighting back. Abc's pierre thomas takes us into the heart of the battle. Reporter: Encounters like this that have fueled the furry. Minorities claiming they are routinely targeted by the nypd stop and frisk program in blatt racial profile. Thisd it happened to him. I remember them banging my head into this. Reporter: He told abc's bill we're it's happening too often. How many times have you been stopped and frisked. Seven times. You're hold old. 17. Reporter: Today a federal judge ruled that they've been engaging in racist by searching those they deem suspicious. 84% of those stopped by police were black and latino males. The men who brought the suit against the city spoke of justice. New york city police department now has to be part of the solution because the judge has agreed with us that it was a big part of the problem. Reporter: The mayor and police chief issued a warning. Let's stop and frisk has saved countless lives and we know that most of those lives saved based on the statistic have been black and hispanic young men. Reporter: The judge is requiring a monitor to oversee nypd practices. And calling for a trial program for some to wear cameras. They do in an increasing number of cities. The ruling could have enormous implications. Stop and frisk sa pretty widely used tactic by police across the country. It's new york city. They've cut homicide significantly.At the same time, how do you balance preventing homicides and constitutional rights? That's the real challenge here. Reporter: Today on a separate front the attorney general said there's simply too many people in prison. And called for measures to reduce that population. Primarily nonviolent offenders. Drug offenders would be the main target, you think? Reporter: Nonviolent drug offenders we're talking some changes could be immediate. He is telling federal prosecutors to reduce the number of cases where they are long-mandatory sentences. We're talking about drug dealers who didn't sell to children who have small amounts of drug,
This transcript has been automatically generated and may not be 100% accurate.