Murder has been on a shocking surge for a year and a half. There are those who want to pretend the cause is a mystery, or that it's a statistical blip, or that even if it's real, It doesn't mean -- in the favorite phrase of those who blink reality -- that "the sky is falling."
It is of course true that the sky is not falling, as it tends not to. But murder is spiking, and it has a cause.
The main cause is that the police have become considerably more cautious due to a cascade of unhinged criticism.
The police deserve and get scrutiny. They are public employees with tremendous power. The problem is not scrutiny. The problem is bansheeism.
The best in the business in diagnosing the what we're facing is Heather MacDonald. Her C-SPAN interview is here.

Bill, I would be very interested to hear about what you think might be now usefully done to reverse what you describe as the main cause of of the recent murder spike.
FWIW, I sense that we are starting to see less "unhinged criticism," perhaps in part because those most likely to promote such criticisms are slowly starting to sense that it is likely having a real impact on public safety. But toned down criticism of late does not seem to yet be "fixing" the murder spike, and perhaps this cannot be repaired in any way in the short term.
Do you think we should seek to return to aggressive stop and frisk in some/all communities experiencing a murder spike? Should we be hiring new cops unlikely to be inclined to be excessively cautious?
Doug,
"Do you think we should seek to return to aggressive stop and frisk in some/all communities experiencing a murder spike?"
Yes. And if they want to stop me, fine. I have never refused to talk to the cops. They're just like everyone else. Most are perfectly reasonable. A few are jerks. According to Gallup, they are far more respected than lawyers like you and me.
"Should we be hiring new cops unlikely to be inclined to be excessively cautious?"
I don't know. I also think that, probably, rookie cops would be inclined to be more cautious than more experienced ones, but I defer to others on that point.
P.S. I'm glad that, after much denial and dismissiveness, the murder spike is now being taken more seriously.