On Monday, speaking at a convention for the International Association of Chiefs of Police in Orlando, Florida, President Trump called for a renewed policy of "stop and frisk." He told his audience that the tactic had made New York City safe, and that it should also be used to cut violent crime in Chicago.

Although working to cut down on violent crime is an admirable goal, an increased policy of "stop and frisk" is the wrong approach.

Trump said that law enforcement in Chicago should “strongly consider 'stop-and-frisk.'” He added that, “It works and it was meant for problems like Chicago. It was meant for it. 'Stop and frisk.' And Rudy Giuliani, when he was mayor of New York, had a very strong policy of 'stop and frisk,' and it went from an unacceptably dangerous city to one of the safest cities in the country, and I think the safest big city in the country. So, it works.”

There's a major problem with this argument. The rise of "stop and frisk" under Giuliani came after most of the decline in crime that occurred during his administration. And there is little evidence backing up the claim that "stop and frisk" actually cuts crime or “works” in any sense of the word, although Trump did claim this before during a 2016 presidential debate.

Beyond those factual objections, the president shouldn’t support "stop and frisk" because it is unconstitutional and blatantly racist in its application.

"Stop and frisk" is known in most places as a "Terry stop." That’s because of a U.S. Supreme Court case, Terry v. Ohio. That case, decided in 1968, established that it was not a violation of the Fourth Amendment, which prohibits unreasonable searches and seizures, if a police officer stops a suspect on the street and does a quick, surface search for weapons without probable cause for arrest.

Terry, however, only stipulates that such a search is acceptable is the officer has a reasonable suspicion that that individual is involved in a committing a crime and has a reasonable belief that that person “may be armed and presently dangerous.” Importantly, the officer making such a stop must have “specific and articulable facts.”

That sounds reasonable. If the officer is worried for his or her safety then they can perform such a stop for their own protection. But that’s not at all how the policy has been applied.

In New York City, where Trump referenced the success of widespread use of "stop and frisk," such stops became the subject of a serious racial profiling controversy. The vast majority of those stopped were African-American or Latino, and the majority of those stopped turned out to be innocent.

At the height of the program (which was long after Giuliani) in 2011, 685,724 people were stopped in New York City. Fully 88 percent of those stops resulted in no conviction. Moreover, officers had been directed to target minority groups. And the number of stops performed, regardless of their constitutional legitimacy, was used as performance metric. In short, police officers seemed to have decided that race alone was enough to meet the threshold of reasonable suspicion, which is illegal.

It also didn’t work. In both 2012 and 2016, studies found that "stop and frisk" wasn’t effective in cutting down on crime. Another study found that if you search a lot of people you might stop slightly more crime, but at great police expense and at the cost of legitimacy, not to mention that such stops are unconstitutional. Moreover, as Kyle Smith explained in the National Review, the abolition of "stop and frisk" didn’t cause crime to rise — instead, it fell.

Besides, the idea of freedom contrasts pretty heavily with the police stopping citizens just because they feel like it, and that’s exactly the sort of thing the Fourth Amendment is supposed to protect us from.

The New York program rightly drew outrage as it was obvious that "stop and frisk," far from the constitutionally permissible stop outlined in Terry v. Ohio, was resulting in racially charged police harassment. A viral video from 2012 helped illustrate how.

In 2013, Floyd v. City of New York found that New York’s policy was both unconstitutional and discriminatory. That resulted in the New York Police Department issuing a mandate that officers had to justify every stop. That quickly cut the number of stops and became a political issue, with Bill de Blasio being elected mayor on a platform of reforming "stop and frisk."

The bottom line is that "stop and frisk" wasn’t the answer to cutting crime in New York, and it won’t be the answer to doing so in Chicago. Rather, all those extra stops and pat-downs did was exacerbate relations between citizens and police and promote racialized policing that violated the rights of citizens.