A memorial to Eric Garner is seen Aug. 20 on a building near where he died in Staten Island in 2014. (Richard Drew/AP)

There are several takeaways from the decision by New York Police Department Commissioner James P. O’Neill to fire the officer whose use of force led to the death of Eric Garner five years ago. It demonstrated that police should be — and can be — held accountable for their actions. Mr. O’Neill was rightly praised by Garner’s daughter for “doing the right thing.” That it took five years — and that the dismissal may not be final if the officer succeeds in his appeal — underscores just how difficult it is to get rid of officers who betray the public trust.

“The unintended consequence of Mr. Garner’s death must have a consequence of its own,” Mr. O’Neill said Monday in announcing that Officer Daniel Pantaleo would be dismissed and stripped of his pension benefits. A police administrative judge this month found the officer guilty of violating a department ban on chokeholds in the July 2014 confrontation with Garner, whose dying words — “I can’t breathe” — were captured on video and galvanized the Black Lives Matter movement.

That the officer was able to stay on the job so long after Garner’s death, working an administrative detail but getting raises and overtime, is infuriating, but sadly not all that unusual. Police departments generally delay disciplinary proceedings while criminal investigations are underway and a determination is made about criminal charges. Too often, there is a lack of urgency, foot-dragging or even worse by these authorities (yes, we are referring to the still-unaccounted-for 2017 shooting in Virginia of unarmed motorist Bijan Ghaisar) that doesn’t serve justice but helps to undermine it.

In the Garner case, did the years-long delay help other officers on the scene evade responsibility for their conduct? A sergeant who arrived on the scene as Garner was pulled to the ground was punished with the loss of 20 vacation days. But what about the officers who failed to provide first aid, or the lieutenant who said in a text that Garner’s death was “not a big deal”? Mr. Pantaleo had four previous substantiated allegations of abuse, more than most other members of the force, and it’s hard not to wonder whether Garner would be alive if the department had done a better job of enforcing its rules and policing its own ranks.

Mr. O’Neill is right: “Being a police officer is one of the hardest jobs in the world.” Not only do officers risk their lives to keep the public safe, but they also must make split-second life-and-death decisions. But those are the very reasons it is in the interest of the both the public and police that there be scrutiny — and meaningful consequences — when it is officers who break the rules.