Of course, states can have their own exclusionary rules, either as a matter of state constitutional law or as a statutory rule. For example, in a couple of Kansas statutory provisions there are explicit exclusionary rules: "no evidence secured in violation of the constitution of the United States or of the state of Kansas shall be admissible." K.S.A. 2005 Supp. 21-4718(b)(5) (upward durational trial departure).
Consider this: is K.S.A. 22-3216, the statute governing procedure for a motion to suppress illegally obtained evidence, a statutory exclusionary rule?
Prior to trial a defendant aggrieved by an unlawful search and seizure may move . . . to suppress as evidence anything so obtained. . . . The motion shall be in writing and state facts showing wherein the search and seizure were unlawful. The judge shall receive evidence on any issue of fact necessary to determine the motion and the burden of proving that the search and seizure were lawful shall be on the the prosecution."The statute seems clear enough--if evidence is obtained by an unlawful search and seizure, it should be suppressed.
This might be important for two reasons. First, if the SCOTUS overrules or limits Mapp v. Ohio, suppression still appears to be the right remedy in Kansas. I suppose if the SCOTUS does take such action, prosecutors might seek repeal or amendment of K.S.A. 22-3216, but legislatively I would rather be on the side of trying to keep a current statute than trying to obtain a new protective statute.
And second, as cogently pointed out by Korey Kaul, perhaps there is an argument that this statute supersedes the Leon v. United States, 468 U.S. 897 (1984), good-faith exception. Leon is an exception to the federal exclusionary rule. But even where the federal exclusionary rule does not apply because of Leon, the statute should still apply. Leon doesn't say that evidence was legally obtained, it only says that the exclusionary rule doesn't apply in certain situations. A defendant in Kansas can still argue that, even if obtained in good-faith, evidence was still obtained "by an unlawful search and seizure" and the remedy under K.S.A. 22-3216 is suppression. If the Legislature had wanted to incorporate a Leon type good faith exception into the statute it could have; but this statute has remained as is since 1971.
Just something to think about. Be sure to cite K.S.A. 22-3216 if the state is pushing Leon on you in an otherwise good suppression case.
[Update: Paige Nichols e-mailed to let me know that she has seen this argument and has made this argument before. It is probably percolating around, although I don't remember seeing an appellate decision on it.]