Hillary Clinton and Donald Trump had a big point of dispute at Monday’s presidential debate — over, of all things, a local crime-fighting policy.

The policy was stop and frisk in New York City. Trump touted its effectiveness in reducing murders and other crime in the nation’s most populated city. Clinton said no, it was not effective at fighting crime, and it violated minority residents’ rights by disproportionately targeting them — leading a court to rule the policy unconstitutional.

When it comes to the stop and frisk debate, the empirical evidence is overwhelmingly on Clinton’s side.

For one, the end of stop and frisk did not lead to a crime wave — which the New York Daily News editorial board, previously a vocal supporter of the tactic, now acknowledges. Studies have also looked at the question, finding that stop and frisk had little to no effect on crime in New York City.

It’s notoriously hard to study these issues — how do you separate stop and frisk from other policing actions and contributors to crime? — but the body of evidence and New York City’s experience show that police departments could stop aggressive overpolicing and use other strategies to make up for the small potential impact of ending stop and frisk.

To Clinton’s point, the policy did have one effect: It massively increased distrust, particularly among black and brown New Yorkers, toward police.

It’s not hard to see why. According to city data, the great majority of people who were stopped and frisked in New York City were minority residents. Almost all turned out to have no contraband on them — meaning they weren’t guilty of a crime. And 1 percent of black people who were stopped had weapons or contraband on them, while 1.4 percent of white people stopped did — suggesting that black people weren’t more likely to be doing anything wrong despite getting stopped more often.

New York City police at the time claimed that they were simply conducting a majority of stops in high-crime areas, which are disproportionately black and brown. But as criminologist Jeffrey Fagan found, even if you controlled for crime, minority New Yorkers were still disproportionately stopped:

The percent Black population and the percent Hispanic population predict higher numbers of stops, controlling for the local crime rate and the social and economic characteristics of the precinct. … The crime rate is significant as well, so the identification of the race effects suggests that racial composition has a marginal influence on stops, over and above the unique contributions of crime.

As a result of these racial disparities, stop and frisk fostered distrust and resentment toward police. That distrust could have actually led to more crime: The evidence shows that police can better solve and prevent crimes if they have the trust and cooperation of their community.

So stop and frisk didn’t have much, if any, of an effect on crime, despite Trump’s claims. But as Clinton said, stop and frisk did disproportionately target black Americans.

Watch: A plea for sanity — and seriousness — in judging the presidential debate