Video technology and terrorism have in many ways revolutionized American policing. Since 9/11, the New York City Police Department (NYPD) has built up a network of some 8,000 surveillance cameras constantly on watch over its streets, tunnels, and bridges. And this week police were able to glean information from grainy captured images, identify a suspect behind last week?s pressure-cooker terror bombing, Ahmad Khan Rahami, and then capture him quickly within a 48-hour span. But what some might call the brave new world of video surveillance has had its flip side, too. Dashboard camera technology, the growing use of clipped-on body cams, and of course the presence of civilian smartphones ? each has become part of a rough-and-ready system of checks and balances between police and civilians, operating now in a fast-evolving landscape in which proliferating digital lenses record more and more encounters on the street.