Duane at Radioblogger assigned me this box of the John Roberts document dump from the Reagan Library. The box contains only the Supreme Court's decision in U.S. v Leon (1984). There is no evidence I can find that John Roberts had made any statement regarding this law while an associate counsel to Reagan, nor anything afterwards. I decided to look in the other part of Box 24 to get some perspective. (Joe Carter is assigned that box, and I apologize if I'm stealing his thunder.) Leon's inclusion appears to stem from a memo he wrote in January 1983 to T. Kenneth Cribb in which he included an Los Angeles Herald Examiner page 1 article from sometime in late 1982 (I see ***mber, 18, 1982, so it could be any of three months) that discussed a study showing 32.5% of drug arrests in LA County in 1981 were thrown out on initial review because of violations of search and seizure laws. "This study should be highly useful in the campaign to amend or abolish the exclusionary rule."

Leon is a victory in amending the exclusionary rule, then, in the eyes of Justice Roberts From The Oyez Project:

The exclusionary rule requires that evidence illegally seized must be excluded from criminal trials. Leon was the target of police surveillance based on an anonymous informant's tip. The police applied to a judge for a search warrant of Leon's home based on the evidence from their surveillance. A judge issued the warrant and the police recovered large quantities of illegal drugs. Leon was indicted for violating federal drug laws. A judge concluded that the affadavit for the search warrant was insufficient; it did not establish the probable cause necessary to issue the warrant. Thus, the evidence obtained under the warrant could not be introduced at Leon's trial.

...The justices held that evidence seized on the basis of a mistakenly issued search warrant could be introduced at trial. The exclusionary rule, argued the majority, is not a right but a remedy justified by its ability to deter illegal police conduct. In Leon, the costs of the exclusionary rule outweighed the benefits.

That seems fairly reasonable. The police acting in good faith on a search warrant should be allowed to gather evidence even if it turns out the judge signing the warrant acted incorrectly in signing it. The exclusionary rule was meant to restrain police abuse, not to let off the guilty. Allowing the police to use evidence gained from a warrant incorrectly issued still provides the deterrent to police overreach. Leon is exactly the kind of case Roberts foresaw in his 2003 memo, and the ruling went his way. The rule was applied in a companion case, Massachusetts v Sheppard where an officer got a warrant signed but on the wrong form -- the Court reversed the Mass. Supreme Court's exclusion of the evidence in a murder case.

Not to say this won't come up in confirmation. The LA Times has flagged Roberts memo (as has the WaPo), while conservatives will point to it as further evidence of his law-and-order credentials. The discussion of the exclusionary rule at Patterico, for example, shows interest in the blogosphere. Leon was a topic of a question asked by Senator Thurmond of Clarence Thomas during the latter's confirmation. But since Thomas two cases have affirmed Leon as best I can tell trying to read quickly some criminal law texts. See US v Gantt (1998) and Arizona v Evans (1995). Thus the good faith exception is part of accepted law, and should Democrats attack Roberts on the basis of this box, they would be arguing against court precedent.