1. May the memory of Police Officers Wenjian Liu and Rafael Ramos be preserved, and may their families be comforted. There can be no justification for their murder - none.
2. The police union's continuing petulance against the mayor, however, demeans both the murdered officers and themselves. Lately, there's been little difference between police unions and the National Rifle Association: both are attempting to enforce an orthodoxy of absolute deference, under which anything less than 100 percent support for their positions 100 percent of the time is intolerable. They're trying to put all public criticism of the police off limits, and any elected official who dares to suggest that the police might have a problem or who doesn't automatically back them in any controversy with civilians is "anti-cop." That's unseemly in a society where the security forces are supposed to be under civilian control and where the role of the police is to serve and protect rather than rule.
3. Predictably police organizations, and people in the law and order camp, are using this as an excuse to reject all introspection and close their ears to criticism on the ground that the protesters are all a bunch of wanna-be cop killers. The New York Post published a stream of hysterical demagoguery along these lines even before the shooting, under the heading "war on cops," and now that a lunatic actually has declared war on cops, it will only get worse.
4. If the possibility of peaceful change is closed off, the crazies will come out of the woodwork. Where there is an occupation, there will be an intifada. I'm afraid this won't be the last time.