The Exclusionary Rule
Calabresi, Guido, Harvard Journal of Law & Public Policy
If there is a litmus test to distinguish between so-called liberals and so-called conservatives in the United States, it is the exclusionary rule. More than one's views on abortion, more than one's views on law and economics, more than one's views on Bush v. Gore, (1) one's position on the exclusionary rule is viewed as a reliable indicator of the side on which one is situated. (2) To liberals, it is a pillar of privacy; it is essential to protect individuals from predations on the part of the police. (3) To conservatives, it is an absurd rule through which manifestly dangerous criminals are let out because the courts prefer technicalities to truth. (4)
Of course, I am not talking about evidence whose veracity is made doubtful as a result of the means by which it was obtained, such as confessions extracted through physical or psychological torture. Rather, I am talking about evidence whose validity or "truthfulness" is unaffected or actually increased as a result of how it was gathered, yet where the method of obtaining the evidence ostensibly violates constitutional or other legal commands. Consider, for example, illegal wiretapping, warrantless searches, and stops that do not meet even the requirements of Terry v. Ohio. (5)
The interesting paradox is this: liberals ought to hate the exclusionary rule because the exclusionary rule, in my experience, is most responsible for the deep decline in privacy rights in the United States. Indeed, the existence of the exclusionary rule has been the reason for more diminutions in privacy protection than anything else going on today. Why is this? Well, the dynamics of this process are very easy to understand.
What, for instance, qualifies as a reasonable search (the Constitution's reference point) is frequently a close question. On the one hand, the police must protect society by catching criminals and by using a variety of means to gather evidence. On the other hand, individual privacy interests may be infringed upon by those means. The judge who seeks to balance these conflicting values in determining whether a search is reasonable, however, finds that there is frequently an enormous thumb on the scale. If the judge holds the search to be unreasonable and therefore excludes the evidence, someone who is manifestly guilty of a very serious crime will be released.
Judges--politicians' claims to the contrary notwithstanding--are not in the business of letting people out on technicalities. If anything, judges are in the business of keeping people who are guilty in on technicalities. Regardless of who appointed her, the judge facing a clearly guilty murderer or rapist who makes a Fourth Amendment or other constitutional claim will do her best to protect the fundamental right and still keep the defendant in jail. It is perfectly obvious: the judge will do so simply because she does not like the idea of dangerous criminals being released into society.
This means that in any close case, a judge will decide that the search, the seizure, or the invasion of privacy was reasonable. That case then becomes the precedent for the next case. The next close case comes up and the precedent is applied: same thing, same thumb on the scale, same decision. The hydraulic effect, as Chief Judge John M. Walker, Jr. has sometimes called it, (6) or the slippery slope, means that courts keep expanding what is deemed a reasonable search or seizure.
You can look around and see how often this has happened. Exigent circumstances, which used to be relatively uncommon, are now everywhere. What was enough to permit a Terry stop used to be quite limited. (7) Today, however, almost anything a policeman says to justify a search is acceptable--and for good reason--because, case-by-case, the precedents have broadened the reasonable search doctrine.
On a side note, it is also my sense that this situation has led police to lie in order to prevent certain evidence from being excluded. …