"Would you be willing to plant corroborative evidence on a suspect you knew was guilty in order to ensure an indictment?"
--James Cromwell as Capt. Dudley Smith in "LA Confidential"
According to the New York Times, a Supreme Court decision has just significantly weakened the "exclusionary rule." This is the principle that says, basically, that evidence obtained against a suspect through improper police procedure may not be used in court (i.e., it must be "excluded"). In this case, Herring v. United States (and you know this is serious if the Solipsist refrains from making some fish-related pun), the Court upheld the conviction of a man who had been arrested because police mistakenly thought, due to sloppy record keeping, that he was subject to an outstanding warrant. In his majority opinion, Chief Justice John Roberts wrote, "To trigger the exclusionary rule, police conduct must be sufficiently deliberate that exclusion can meaningfully deter it, and sufficiently culpable that such deterrence is worth the price paid by the justice system" (i.e., letting a guilty man go free).
The logic of this opinion was propounded by that tribune of liberal thinking, Antonin Scalia, who said that the exclusionary rule, established in the 1961 case Mapp v. Ohio, was no longer relevant, due to increased police professionalism and the expanded rights of citizens to seek legal redress for police misconduct. As a prominent criminologist wrote, however, Scalia was mistaking cause and effect; that is, police had become more professional largely BECAUSE of Mapp, and eliminating its protections would jeopardize any such gains. (As a general rule, if Scalia is for it, the Solipsist is against it.)
(Digression: One cannot help but find in Scalia's reasoning an echo of the famous torture-approving Justice Department memo that declared the Geneva Conventions "quaint." End of digression.)
In theory what this means is that criminals who are "clearly" guilty will no longer be able to game the system by claiming that their stockpiles of illegal AK-47's cannot be used against them in court because the search warrant misspelled "Kalashnikov." All well and good. But the slope is more than a little slippery. In a subsequent New Jersey case, a man was convicted based on evidence found on his computer hard drives. But the warrant for searching the hard drives was issued based on FALSE information.
Now, it would be easy to find egregious examples of vile criminals released on technicalities. Indeed, in the case mentioned above, the crime appears to be child pornography (the article is strangely vague on the matter), and nobody is going to be too upset about a child pornographer going to jail. But that's the point. Constitutional protections are not supposed to be adjustable based on the relative likability of defendants. And do we really want to encourage FBI agents to lie about evidence in order to obtain search warrants? Is it a good idea to start down a road that leads to police barging randomly into people's homes on the belief that they'll find evidence of crimes? If that becomes the case, God help us all when police feel the need to start meeting arrest quotas.
Essentially, the Roberts decision seems to offer the possibility of an "Oops" defense. "Look, guys, we found a marijuana plant in this guy's closet. Oh, we had the wrong address on the search warrant? Oops!" Lock him up!