The Exclusionary Rule

The NY Times ran this article yesterday on what's known as the Exclusionary Rule. In1914 the Supreme Court ruled in Weeks v. United States that if law enforcement officials find evidence by breaking the law or violating your Constitutional rights, they can't use that evidence against you in a federal court. The Rule was then extended to the local and state level in Mapp v. Ohio (1961). While there's a good deal of nuance in the various opinions handed down by the Supreme Court, there is one important exception: if the police can prove that they would have uncovered the evidence in question if they hadn't broken the law or violated the Constitution, the evidence is admissible.

So, for example, if the police break into my home without a search warrant and find that I have a giant cocaine factory in my basement, they can't use the evidence they found in my house to convict me. If, however, the police can prove that they could have had a judge sign a search warrant and uncovered the evidence that way, i.e., without violating my rights, then the evidence is admissible, and I'm pretty much screwed.

The Times article clearly indicates that the Rule is controversial and that many people think it ought to be thrown out. In my not-so-humble opinion, that's just plain wrong: the Exclusionary Rule needs to be kept in place. Three important points:

1. The only evidence the Exclusionary Rule excludes is evidence that the police didn't obtain legally and can't even prove they could have obtained legally. I can't think of a single good reason why the police should be entitled to use evidence that they had no right to have found in the first place. The Exclusionary Rule just makes sure that the outcome of a case is the same as it would have been if everyone followed the rules. It's the same principle referees use in assigning penalties in football, or any other sport: the penalty is intended to take away any advantage the offending team got by not playing by the rules.

2. In that same vein, if the police broke the law but can prove that they could have gotten the evidence legally, they can use it. The same principle is at work here: by allowing the evidence to be used, the judge is making sure the outcome is again the same as it would have been if the police obeyed the law.

3. The major argument the Times emphasized in getting rid of the Exclusionary Rule has to do with the supposed social cost: "The criminal is to go free because the constable has blundered.” Unfortunately, that's not an accurate characterization of what happens: it's not as though the police have an air-tight case and because of some legal technicality the criminal gets off; the police wouldn't have had a good case to begin with if they hadn't violated the defendant's rights. The criminal doesn't go free because the constable blundered; the criminal goes free because there was no way to legally get the evidence needed to convict him or her.

One final example. Consider two cases:

Case 1: a 7-11 is robbed, and the police believe Joe is the culprit. The police believe the money Joe stole is in his house, but they don't have probable cause to get a search warrant. Since these are good, law-abiding police officers, they're forced to let Joe go and not charge him with burglary.

Case 2: a 7-11 is robbed, and the police believe George is the culprit. The police believe the money Joe stole is in his house, but they don't have probable cause to get a search warrant. Since these aren't particularly good police officers, they chose to break into his house anyway, knowing it's a gross violation of his rights. The police find the stolen money and charge George.

If we were to abolish the Exclusionary Rule, Joe would get off, but George would be convicted of burglary. Not that I don't like the idea of George being charged for something he's guilty of, but here's the problem: George is convicted because the police violated his rights.

Does anyone really believe that's not unjust?