In Collins v. Virginia, decided yesterday, the Supreme Court held that a warrantless search of a motorcycle parked on private property violated the Fourth Amendment, and thus that evidence found in the search should be excluded in the prosecution of Collins. Justice Thomas concurred but objected on originalist grounds to the imposition of the exclusionary rule in state cases. First he argued that the rule is (as the Court has said) not required by the Constitution (footnotes and some [but not all!] citations omitted):
The assumption that state courts must apply the federal exclusionary rule is legally dubious, and many jurists have complained that it encourages “distort[ions]” in substantive Fourth Amendment law ...
...
While those who ratified the Fourth and Fourteenth Amendments would agree that a constitutional violation occurred here, they would be deeply confused about the posture of this case and the remedy that Collins is seeking. Historically, the only remedies for unconstitutional searches and seizures were tort suits and self-help. The exclusionary rule—the practice of deterring illegal searches and seizures by suppressing evidence at criminal trials—did not exist. No such rule existed in “Roman Law, Napoleonic Law or even the Common Law of England.” Burger, Who Will Watch the Watchman? 14 Am. U. L. Rev. 1 (1964). ...
Despite this history, the Court concluded in Mapp v. Ohio, 367 U. S. 643 (1961), that the States must apply the federal exclusionary rule in their own courts. Mapp suggested that the exclusionary rule was required by the Constitution itself. ... But that suggestion could not withstand even the slightest scrutiny. The exclusionary rule appears nowhere in the Constitution, postdates the founding by more than a century, and contradicts several longstanding principles of the common law. See supra, at 2–3; Cuddihy 759–760; Amar, Fourth Amendment First Principles, 107 Harv. L. Rev. 757, 786 (1994); Kaplan, The Limits of the Exclusionary Rule, 26 Stan. L. Rev. 1027, 1030–1031 (1974).
Recognizing this, the Court has since rejected Mapp’s “‘[e]xpansive dicta’” and clarified that the exclusionary rule is not required by the Constitution. Davis v. United States, 564 U. S. 229, 237 (2011) (quoting Hudson v. Michigan, 547 U. S. 586, 591 (2006)). ...
But, the concurrence continues, if the exclusionary rule isn't required by the Constitution, how can it be enforced against the states? Only as, in effect, federal common law -- which Justice Thomas also finds dubious on originalist grounds:
Federal law trumps state law only by virtue of the Supremacy Clause, which makes the “Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties . . . the supreme Law of the Land,” Art. VI, cl. 2. When the Supremacy Clause refers to “[t]he Laws of the United States made in Pursuance [of the Constitution],” it means federal statutes, not federal common law. Ramsey, The Supremacy Clause, Original Meaning, and Modern Law, 74 Ohio St. L. J. 559, 572–599 (2013) (Ramsey) [Ed.: hey, that sounds familiar!); Clark, Separation of Powers as a Safeguard of Federalism, 79 Texas L. Rev. 1321, 1334–1336, 1338–1367 (2001) (Clark); ...
By referencing laws “made in Pursuance” of the Constitution, the Supremacy Clause incorporates the requirements of Article I, which force
Congress to stay within its enumerated powers, §8, and follow the cumbersome procedures for enacting federal legislation, §7. See Wyeth v. Levine, 555 U. S. 555, 585– 587 (2009) (THOMAS, J., concurring in judgment); 3 J. Story, Commentaries on the Constitution of the United
States §1831, pp. 693–694 (1833); Clark 1334. Those procedures—especially the requirement that bills pass the Senate, where the States are represented equally and Senators were originally elected by state legislatures—safeguard federalism by making federal legislation more difficult to pass and more responsive to state interests. See Ramsey 565; Clark 1342–1343. Federal common law bypasses these procedures and would not have been considered the kind of “la[w]” that can bind the States under the Supremacy Clause. See Ramsey 564–565, 568, 574, 581; Jay, Origins of Federal Common Law: Part Two, 133 U. Pa. L. Rev. 1231, 1275 (1985).
...
True, this Court, without citing the Supremacy Clause, has recognized several “enclaves of federal judge-made law which bind the States.” ... These precedents do not support requiring the States to apply the exclusionary rule. As explained, the exclusionary rule is not rooted in the Constitution or a federal statute. This Court has repeatedly rejected the idea that the rule is in the Fourth and Fourteenth Amendments, expressly or implicitly. And the exclusionary rule does not implicate any of the special enclaves of federal common law.
And in conclusion:
In sum, I am skeptical of this Court’s authority to impose the exclusionary rule on the States. We have not yet revisited that question in light of our modern precedents, which reject Mapp’s essential premise that the exclusionary rule is required by the Constitution. We should do so.
Thanks to Justice Thomas for citing my article, among others, and I'm happy to see that my thinking on federal common law is similar to his. (My article doesn't say anything about the exclusionary rule but I think the Justice is right about its implications).
A note on the merits of Collins: I think this is another case where originalism provides a more definite answer than nonorignalism. Justice Alito dissented in an nonoriginalist opinion arguing that the actions of the police were reasonable, mainly because they were minimally intrusive. Quite arguably, he's right under the modern sense of "reasonable." But as Justice Thomas notes briefly, the historical rule appears to have been that police needed a warrant to search a house or its "curtilage," absent some narrow exceptions not relevant in Collins. (See my earlier thoughts on Collins here). On the other hand, as Orin Kerr points out, defining the "curtilage" may sometimes be a problem, and maybe it was more of a problem here than the Court thought: Collins v. Virginia and "the Conception Defining the Curtilage".