Whether and to what extent the police can affect homicide rates is very obviously a key debate about the effectiveness of public policing. In their article the authors seek to explore this issue by examining the relationship between a phenomenon they describe as “de-policing” and the homicide rate. Their measure for the extent of policing activity or its converse, “de-policing”, is the global arrest rate across a selected group of North American cities. The article raises many questions and appears to find few clear answers. Indeed, the authors find little support for the relationship between arrest and homicide rates. Instead, they devote their conclusions to a series of wider implications about targeted patrol and legitimacy.