In a piece at Politico today, David Rittgers raised a number of important points on the role of surveillance cameras in law enforcement, about which I blogged yesterday at Politico Arena and Cato@Liberty. To add still more to the subject, David is quite right: the cop on the beat, assuming he’s there, will be better than the camera at preventing crime. In at least two cases, however, cameras can fight crime not only ex post but ex ante as well. First, cameras monitored in real time — as private cameras often are in apartment buildings, casinos, warehouses, and elsewhere — can facilitate crime prevention by alerting monitors to suspicious activity. And second, would-be criminals who are concerned about being caught may think twice if they suspect they’re being monitored. Cameras will not deter suicide bombers, of course; nor will they deter those who are unaware they’re being monitored, as may have been the case with the incompetent bomb maker in Times Square – who seems at this writing (we await more facts) to have wanted to “get away,” all the way to Pakistan.

But to add further to the civil liberties point I made yesterday, not only are surveillance tapes usually more accurate that eyewitness accounts in identifying criminals, thereby lessening the very real problem of mistaken prosecutions and convictions, but they aid also in the equally real problem of police (and even prosecutorial) abuse. Two weeks ago David blogged about the recent University of Maryland case involving the notorious Prince George’s County police department, where a video showed police brutality that the police later falsified in their report. And surveillance tapes can work in the other direction too — to protect police from false accusations of brutality. So the civil liberties implications of surveillance cameras are many, and often not what they seem on first impression.