All the while, Mr. Pantaleo continued to serve on the force, even seeing his overtime pay increase in the year after Mr. Garner’s death.

The city’s police union responded to the commissioner’s decision on Monday with its own form of resistance. “We are urging all New York City police officers to proceed with the utmost caution in this new reality, in which they may be deemed ‘reckless’ just for doing their job,” the Police Benevolent Association president, Patrick Lynch, said in a statement, appearing to call for a work slowdown. “We will uphold our oath, but we cannot and will not do so by needlessly jeopardizing our careers or personal safety.”

It’s important that Mr. O’Neill and Mayor Bill de Blasio brush off the bombast while continuing to give officers the support they need.

In the past, New York has been too reluctant to discipline its police officers, with grave consequences. Particularly troubling is evidence suggesting that officers rarely face discipline for using chokeholds, even though the move is banned.

Mr. Pantaleo had four substantiated allegations of abuse against him before he choked Mr. Garner — far more than a vast majority of members of the force.

Mr. Garner’s family has suffered immensely. His daughter Erica Garner died in 2017 of a heart attack after years of activism in the wake of her father’s death. Mr. Garner’s stepfather, Benjamin Carr, died of a heart attack last month. Mr. Garner’s mother, Gwen Carr, has been tireless in seeking justice for her son. It is a small mercy, at least, that she has seen something approaching justice done.

The lack of accountability in Mr. Garner’s death has also remained an open wound in the city, adding to a sense of grievance against the police among black and Hispanic New Yorkers even as crime rates were falling to record lows.