Formally it was the job of the police to murder defenseless black youths*, but numerous cutbacks have weakened public police departments. Much of law enforcement has been privatized. Rich men hire security guards to defend their co-op apartments and gated Shangri-La’s. Poorer neighborhoods have tapped a zeal for volunteering. Just as most of the Internet is written for free — including this essay — the “neighborhood watch” stands vigil over our streets without payment. When a policeman guns down an unarmed black boy, all of society is responsible. When a “neighborhood watcher” like George Zimmerman does so, it’s a “tragic miscalculation.” (Is that the phrase the right-wing talk show host used last night?) In our new “volunteer economy,” much of the workforce is untrained. Just as this essay lacks clear citations & polished argument, Mr. Zimmerman’s amateur policing lacks focus. He had no intention of murdering Trayvon Martin; he blundered into it through hubris, paranoia and a cheap gun. None of us are responsible, as we are when a cop, whose salary we pay, kills a teenager walking home from a 7-Eleven.