The nonpartisan Pew poll just confirmed the existence of the so-called “Ferguson effect”: 86 percent of cops polled say all the national controversy over police killings of civilians has made their jobs tougher.

The St. Louis police chief coined the term after the shooting of Michael Brown, to describe the tendency of officers to back off from proactive policing in the wake of widespread protests. The Manhattan Institute’s Heather Mac Donald and others point to the Ferguson effect to help explain the rise in violent crime in many US cities.

Pew polled some 8,000 police officers on race relations, morale and reform last year — with most of it done before the assassinations of cops in Dallas and Baton Rouge.

Key findings:

93 percent of officers say they’ve grown more concerned about their safety.

76 percent are more now reluctant to use force when necessary.

75 percent believe interactions between police and blacks have become more tense.

72 percent say they’re more reluctant to stop and question suspicious-looking people.

67 percent report being verbally abused.

Of course, none of this justifies any police abuse, nor delegitimizes any given protest.

But it does flag the perils of a rush to judgment — as in the Ferguson case itself, where the Obama Justice Department’s investigation fully confirmed the account of the officer who shot Brown, and shredded the “Hands up, don’t shoot” claim that Brown was an innocent victim.

Luckily for this town, the NYPD has kept bringing crime down, despite the national trend, and local challenges from the death of Eric Garner to the City Council’s ongoing efforts to handcuff law enforcement.

New York City government doesn’t have much to teach the rest of urban America, but policing remains the standout exception.