To Joel Jacobson, and his new blog “Judging Crimes.” Jacobson, an assistant attorney general in New Mexico, has a number of great posts up already, including this empirical investigation into deterrence and the Fourth Amendment. Here is a taste:
The Supreme Court has repeatedly told us that the suppression of evidence deters wrongdoing by police. Lower court judges accept this as fact for a very good reason: the Supreme Court says so. But the rest of us can be little more skeptical. Using the sabermetric principle that if a phenomenon exists, it must inevitably show up in the statistics, I looked for evidence that the judiciary’s fourth amendment jurisprudence has had a deterrent effect.
My working hypothesis was that if the exclusionary rule has any overall tendency to deter police from making unconstitutional searches and seizures, the number of cases in which the legality of a search/seizure was challenged should have peaked relatively soon after 1961 and then gone into a steady decline. As more and more officers were deterred, it seems reasonable to suppose, ever-fewer would still need deterring.