Donald Trump’s closing comment in Wednesday night’s presidential debate included what has become a frequent theme for him: how awful life is in “the inner cities” for people of color — whom he refers to as “the African-Americans” and “the Latinos.” Here’s what he said:

Our inner cities are a disaster. You get shot walking to the store. They have no education, they have no jobs. I will do more for African Americans and Latinos than [Hillary Clinton] can ever do in 10 lifetimes. All she has done is talk to the African Americans and to the Latinos.

Trump didn’t explain what he would do exactly — or at all. And he hasn’t done that throughout the campaign. It’s worth noting that his only specific proposal related to African Americans this campaign season came in response to a question in a September “African-American town hall” meeting about what he would do to address “violence in the black community.” His idea: to revive stop and frisk, a New York City policing program that was been deemed unconstitutional because it did the very opposite of helping black and Latino people — it unfairly targeted them.

Here was his response at that event:

Right, well, one of the things I’d do, Ricardo, is I would do stop and frisk. I think you have to. We did it in New York. It worked incredibly well and you have to be proactive and, you know, you really help people sort of change their mind automatically, you understand, you have to have, in my opinion. I see what’s going on here, I see what’s going on in Chicago, I think stop and frisk. In New York City, it was so incredible, the way it worked. Now, we have a very good mayor, but New York City was incredible, the way that worked, so I think that could be one step you could do.

What he said was jarring on one level because it seemed to reveal that he was unaware of the many problems with stop and frisk. But even more alarming was that he suggested a revival of the program in response to a question about how to address “violence in the black community” specifically.

That suggests it’s the very unconstitutional quality that got the policy struck down in New York — its racially biased application — that Trump would like to replicate.

Because his comments were in response to a question about “the black community” generally, and referred to what he would do as president, they were initially read as a proposal to recreate stop and frisk across the country. Trump dialed that back later that week on Fox & Friends, saying that his suggestion applied only to Chicago. Regardless of the scale, it’s a terrible idea.

The New York City stop-and-frisk policy that Trump wants to replicate was a massive, racially biased, ineffective, unconstitutional failure

Trump’s statement suggests he is unaware that stop and frisk in New York was a failure on multiple levels. Mother Jones’s Hannah Levintova summed it up on Wednesday in a piece on Trump’s comments: The policy was implemented in a way that unfairly targeted black and Latino residents — effectively, racial profiling.

Because of that, a federal judge determined in 2013 that the way New York City enforced the policy — the city whose program Trump says was “incredible” and that he’d like to recreate — was unconstitutional. That decision was based on the finding that officers operating under the policy showed disregard for the Fourth Amendment’s protections against unreasonable searches and seizures as well as the 14th Amendment’s Equal Protection Clause.

Trump’s apparent ignorance of or disregard for these things, combined with his push to bring the program specifically to Chicago’s black communities, sounds like recipe for a replica of the racially biased New York City policy that was struck down.

Moreover, since New York City has abandoned stop and frisk, despite supporters’ fears and warnings, crime rates have not gone up. In other words, the policy didn’t even work.

In August, the New York Daily News editorial board — which had previously warned that getting rid of stop and frisk would end New York City’s decades-long decline in crime — admitted that the end of the policy did not in fact cause crime to go up, writing:

We are delighted to say that we were wrong. The NYPD began scaling back stops under Kelly before Scheindlin’s decision and accelerated the trend under Commissioner Bill Bratton. As a result, the number of stops reported by cops fell 97% from a high of 685,700 in 2011 to 22,900 in 2015. Not only did crime fail to rise, New York hit record lows. The murder count stood at 536 in 2010 and at 352 last year — and seems sure to drop further this year. There were 1,471 shooting incidents in 2010 (1,773 victims). By 2015, shootings had dropped to 1,130 (1, 339 victims). The downward march has continued this year — a marked contrast to crime spikes in many major American cities.

So even those who would be fine with racial profiling, so long as it lowered crime, don’t have anything to be in favor of here.

Vox’s German Lopez observed that this revelation seemed significant in ways that were bigger than New York City:

Stop and frisk grew to be controversial on a national scale because it became a symbol of excessive policing practices, particularly in minority communities — the kind that have triggered massive protests around the country over racial disparities in policing and the criminal justice system. So the fact that even leading proponents of these practices are now admitting they were wrong — and that aggressive policing practices can end without leading to more crime — is a very good sign for the future of police reforms.

It was impossible to predict even two months ago that a candidate for president would be unaware of or disregard this consensus and argue to expand the policy. But in a way, his interest in stop and frisk mirrors the ban on Muslims entering the United States that Trump proposed last year: He’s embracing something that’s not just unconstitutional but also totally incapable of solving the problem he hopes it will. And he doesn’t seem to care about either of these things.

Overpolicing black communities for minor offenses is part of a deep, nationwide problem

Part of the reason New York City’s stop-and-frisk program was deemed unconstitutional was the judge’s finding that “[b]lacks are likely targeted for stops based on a lesser degree of objectively founded suspicion than whites.” What kinds of things caused suspicion of black residents? Often, “furtive movements.” What are “furtive movements”? The New York Times, in reporting on the decision, explained in 2013 that that category included the following:

Being fidgety

Changing directions

Walking in a certain way

Grabbing at a pocket

Looking over one’s shoulder

Trump’s enthusiasm for a policy under which police target people in black communities for minor sources of suspicion represents the exact approach studied by David Kennedy. Kennedy, a professor at John Jay College of Criminal Justice and director of the National Network for Safe Communities, has argued that approaches like these contribute to black communities being overpoliced (for minor offenses) and underpoliced (when it comes to addressing serious crimes) at the same time.

In a 2015 piece for the Los Angeles Times, Kennedy took readers through a thought exercise that explains how counterproductive this imbalance is. Imagine, he wrote, facing relentless harassment by police for small offenses but being ignored when it comes to serious public safety issues. Imagine knowing that law enforcement officials in your neighborhood "think you're all scum," and doggedly pursue you and your friends for things like marijuana possession and loitering, but check out when it comes to holding people accountable for actual violence:

You'd be experiencing what families in stressed black neighborhoods have experienced forever — very high rates of arrest for minor offenses white folks routinely get away with, and shockingly low arrest rates for serious violent crime. The cause of the latter is not as simple as deliberate police withdrawal — it's a toxic mix of a terrible history of exactly that, and a nearly as toxic present of mistrust, broken relationships and bad behavior on both sides — but the result is the same. Being overpoliced for the small stuff, and underpoliced for the important stuff, alienates the community, undercuts cooperation and fuels private violence: which itself often then drives even more intrusive policing, more alienation, lower clearance rates, and still more violence. The cops write off the community even more; the community writes off the cops even more.

He’s not the only expert who sees this pattern. Jill Leovy, author of Ghettoside, which won the PEN Center USA’s award for research nonfiction in August, has argued that the very type of overpolicing Trump is excited about contributes to the sense that the law has lost its legitimacy in many black communities.

“Imagine that you’re a student at a school,” Leovy posed in a recent interview with Vox. “There are bullies at the school, and the bullies beat you up every day on the playground. But the only time the playground supervisor comes around, he or she says, ‘Don’t chew gum on the playground,’ and walks away, and ignores the bruises and the fighting. You would be cynical. You would cease to believe in the system. …

“Like the schoolyard bully, our criminal justice system harasses people on small pretexts but is exposed as a coward before murder. It hauls masses of black men through its machinery but fails to protect them from bodily injury and death. It is at once oppressive and inadequate.”

The point is that black neighborhoods have too much and not enough police involvement at the same time. And Trump, in his stop-and-frisk proposal, is arguing for more of the kind that already exists in excess. It shows a disturbing embrace of racial profiling, ignorance of what the Constitution would allow, and a failure to distinguish between tactics that might make communities safer and those that could actually make them more dangerous.