In this case, Mr. Trump was trying to get at an even bigger untruth.

More than 4 million innocent people were stopped and frisked between 2002 and 2012. Most were under the age of 25. The vast majority were black or Latino. Under pressure from a lawsuit, the practice was scaled back beginning in 2012 — not by the order of a judge, not by Mayor de Blasio, but by his predecessor, Michael R. Bloomberg.

Today, the police still stop and search people, but the number of such encounters has dropped by more than 98 percent since its peak in 2011 — down to 12,404 in 2016, and about the same pace this year. Six years ago, 685,724 were stopped and searched — 605,328 of whom had done nothing wrong, and many thousands who had done nothing worse than carry marijuana.

Along the way, a federal judge did say that the city’s wholesale stop-and-frisk practices violated the Constitution. But contrary to the cries of Mr. Bloomberg, the police commissioner and some editorial writers, further curtailing this approach did not make the city more dangerous. In fact, the opposite happened. That is unambiguously great news.

In the six years since the police department began cutting back on searches, murder in the city has dropped by almost half. The department now puts its resources on groups — gangs — that it sees as likely to be victims or perpetrators of crime, or both.

Other realities: The city’s economy is booming. Jobs have grown for 90 straight months. “It’s wrong to say that the police are completely responsible for the murder decrease,” said Stephen P. Davis, the Police Department’s deputy commissioner for public information. “It’s also wrong to say these other factors, like the economy, are the only reason.”

Stop-and-frisk was like an opioid that had been so overused that it no longer relieved pain, but created a relentless appetite for more drugs. Leaving aside the offense to civil rights and human decency, the tactic now looks as idiotic as putting opioids or antibiotics in the water system on the theory that even if hardly anyone needed them, the medicines would ease some pain or cure some disease. Fortunately, it is now being used with greater discretion.

Some people still miss the drug.

Regular coverage of the apocalypse resumes shortly.