One spring evening in 2014, Charles Collins, a 67-year-old black Milwaukee resident, was driving back home with his wife. They had just dropped off their grandchild at their son's house after a day of babysitting.

"We were returning home, driving along, talking, just having a great interaction. You know, wife and husband, kicking it," Collins recalls. "Out of nowhere a policeman pulled up behind us with lights on."

When the Milwaukee police officer approached Collins and asked for his license, Collins handed it over and asked if there was any problem with his car of if he'd been speeding.

"We're not the ticket police," the officer replied, according to Collins.

The officer noticed Collin's concealed handgun license and asked him if he had any weapons in the car. When Collins said no, the officer went back to his cruiser, returned a short while later, handed Collins' license back, and let them go. The officer never said why he pulled Collins over.

The husband and wife drove away, stunned and confused. Although not too confused. The same thing had happened to Collins several times over the years, just as it had to his son and many of his friends, both young and old.

"As a brother or black man living in Milwaukee, it's not an unusual thing," Collin says. "When I leave my home, I leave with apprehension. Not that it's in your face, but it's there. I feel there's a good possibility that I'll get shot or pulled over. It's in me, you know what I'm saying? I can feel it."

Now Collins is one of the lead plaintiffs in a federal class-action lawsuit the American Civil Liberties Union is filing against the Milwaukee Police Department for operating what it says is an unconstitutional and racially discriminatory stop-and-frisk program.

The ACLU lawsuit, to be filed early Wednesday morning, alleges the Milwaukee Police Department subjects city residents like Collins to high-volume, suspicionless stops and searches as part of a quota system, violating their Fourth and Fourteenth Amendment rights.

"The named plaintiffs' experiences of being stopped, frisked, and searched by MPD officers without legal justification are far from isolated incidents," the lawsuit says, according to a copy obtained by Reason. "They are the result of the MPD's high-volume, suspicionless stop-andfrisk program, which violates both the Fourth Amendment prohibition on unreasonable searches and seizures and the prohibition against racial and ethnic profiling under the Fourteenth Amendment and Title VI of the Civil Rights Act."

While police officers have the authority to pull someone over if they have reasonable suspicion of criminal activity, "the problem arises when officers are stopping someone for no good reason, which is exactly what's happening in many instances in Milwaukee," ACLU attorney Jason Williamson says in an interview. "All the plaintiffs in this case were going about their daily lives, visiting friends, driving home from a relative's house. To have that life disrupted by the police for no good reason is traumatic and illegal."

Milwaukee Police Chief Ed Flynn, who has led the department since 2008, is a steadfast disciple of the "broken windows" theory of policing—the idea that heavy police presence in a community, combined with proactive enforcement of low-level nuisance crimes, will deter more serious crimes. The theory gained prominence, and notoriety, in New York City in the early '90s, where it was embraced by city officials and loathed in many of the minority communities subjected to it.

Flynn has also adopted New York City's CompStat model, which relies on sophisticated technology and statistics to monitor crime trends and measure individual officers' performance.

Under Flynn, the combined number of Milwaukee police traffic and pedestrian stops nearly tripled between 2007 and 2015, rising from 66,657 in 2007 to 196,434 in 2015, according to the lawsuit. The ACLU says CompStat's devotion to numbers turned these stops into a both formal and informal quota system for officers.

And digging into those numbers revealed minorities bore the brunt of this police saturation. A 2011 investigation by the Milwaukee Journal-Sentinel found black drivers were seven times as likely to be stopped by city police as white drivers, and twice as likely to be searched by police.

However, Flynn has defended the strategy, saying it logically focuses on neighborhoods where crime occurs most.

"Here's what's disproportionate to me," Flynn said in a 2013 interview. "With about 40 percent of Milwaukee's population, African-Americans represent 80 percent of our homicide victims. They represent 60 percent of our robbery victims and 80 percent of our aggravated assault victims."

Flynn had his work cut out for him when he took over the Milwaukee Police Department in 2008. It was a troubled department in one of the most segregated cities in the U.S., already suffering from poor community relations, and while he was devoted to improving police work—he rewrote the code of conduct and transferred hundreds of officers out of their cruisers and put them on foot patrols so they could interact with residents—his department continued to be plagued by problem officers and several high profile police shootings.

In 2014, shortly after the deaths of Michael Brown in Ferguson and Eric Garner in New York City at the hands of police, a Milwaukee police officer shot and killed Dontre Hamilton, a 31-year-old man with a history of mental illness, during an altercation. Hamilton had been sleeping on a park bench when the officer confronted him and tried to pat him down. The officer was fired, but the incident sparked protests and calls for major reforms in the city's police force.

"We were in touch with our local affiliate in Milwaukee," Willamson says of the ACLU's involvement shortly after Hamilton's death, "and it was clear to us that there was a long history in the city of contentious relations between the Milwaukee Police Department and communities of color, and that there was a serious lack of trust that had developed because people in black and latino communities didn't feel like they were being treated fairly by police just on a day-to-day basis. The more we dug into it and more people we spoke to the more we realized this was something we needed to try and address."

Over the past several years, dozens of Milwaukee residents have filed lawsuits against the Milwaukee Police Department for unconstitutional stops. In 2016, the city paid out $5 million to 74 black residents who said they were illegally strip searched. However, Wednesday's suit is only the third in the U.S. challenge the practice at an institutional level in a large U.S. city.

Other major cities have fared poorly defending stop-and-frisk policies. Philadelphia entered into a consent decree in 2011 as a result of a lawsuit. In 2013, a federal judge ruled the NYPD's stop-and-frisk policy was unconstitutional and discriminatory. Investigations by the Justice Department's Civil Rights Division found similar patterns of unconstitutional stops and searches in Baltimore and Chicago.

Flynn has continued to defend stop-and-frisk tactics overall, although he said the NYPD's policy continued long after drops in crime should have led to its end, creating resentment within New York City minority communities. "There's no question it worked," Flynn said of New York's stop-and-frisk program last year. "Going from 2,200 homicides to under 300 homicides."

However, the NYPD Inspector General released a report last year that found no correlation between the NYPD's enforcement of low-level crimes and drops in more serious crime. And after the NYPD's use of stop-and-frisk essentially ended, crime in New York City continued to drop.

One of the other plaintiffs in the ACLU suit, a juvenile identified only as D.A., was stopped three times by Milwaukee police, according to the lawsuit: once when he was in fifth grade on a friend's porch; again in 7th grade, while cutting through an alley on the way to a friend's house; and again in high school, while walking to school. In every instance, the lawsuit says, he had done nothing.

"Yes, of course, we are going to stop lots of innocent people," Flynn said in his defense of his department in 2011. "The point is, do folks understand what their role is as a cooperative citizen in having a safe environment. That level of inconvenience, if it's coupled with respectful treatment, is something communities will accept to be safe."

But that argument holds little legal water for Williamson.

"There's been some suggestion in Milwaukee and other parts of the country that, if you are a resident in a neighborhood that has a crime problem, you should be willing to forgo some of your rights for the safety of your community, and is it too much to ask to stop you for a minute or two to make sure everyone is safe?" he said. "It can't be underestimated how humiliating and degrading these sorts of interactions are, to be treated like a criminal suspect, I don't care how long the encounter lasts. It is not a small price to pay for people who are living in these communities to have to deal with this, and it's not an unreasonable request for people to want to have their communities protected without ceding their constitutional rights in exchange."

It makes even less sense for Collins, whose experience as a data point in the Milwaukee Police Department's CompStat program left him feeling no safer.

"I'm cruising along, not speeding, my wife and I having a conversation," he says. "We're not doing anything. It's a nice evening. Sun's going down. Stopping me, how's that helping anything? I understand crime, but how's that going to help me?"