As Eugene noted, a divided panel of the Ninth Circuit recently held that a child pornography conviction had to be reversed because the evidence was gathered in violation of the Posse Comitatus Act. Steve Vladeck has a post discussing the important and potentially certworthy issue in the case, which is whether a violation of that statute can trigger the exclusionary rule at all.

I confess that my initial reaction was skepticism. Consider Sanchez-Llamas v. Oregon:

We have applied the exclusionary rule primarily to deter constitutional violations. [In t]he few cases in which we have suppressed evidence for statutory violations the excluded evidence arose directly out of statutory violations that implicated important Fourth and Fifth Amendment interests.

Maybe the Posse Comitatus Act can be shown to implicate important Fourth and Fifth Amendment interests, but the Ninth Circuit didnt really show that, and it isnt obvious to me.

More generally, it seems to me that current exclusionary rule doctrine can be read in a couple of different ways:

One is the deterrence theory: Exclusion is appropriate when it seems like theres intentional and/or widespread and/or generally problematic illegality by the government. This refrain appears in a bunch of the cases, and its how the Ninth Circuit framed the analysis. Its not clear, however, that the analysis automatically applies in statutory cases (see above).

A second is the slow destruction theory: Under this theory, the exclusionary rule is unfounded and deleterious, and the rule and its works should be slowly destroyed. Some people read the Courts exclusionary rule precedents to be implicitly working toward this theory. It is not really put forward by the Court as a first-order justification, although quite a few of the opinions do frame their analysis by questioning the rules basis or justification.

Until recently, I would have ended this list there. But I have recently begun to give some credence to a third account of exclusionary rule doctrine put forward by my friend Richard Re in an article called The Due Process Exclusionary Rule.

Richard argues that today many searches and seizures should be seen as part of the criminal process and that the exclusionary rule is thus justified by the Due Process Clause, which forbids a conviction obtained through illegal process. While I am not yet sure that I agree with this view, I think it deserves serious consideration, and is the best alternative to the slow destruction theory that is on offer.

Here is what the article says about statutory violations (footnotes omitted):

See more here:

Volokh Conspiracy: What the posse comitatus case might mean for the future of the exclusionary rule