On May 30th, the Supreme Court issued its decision in Collins v. Virginia, which held that the “automobile exception” to the Fourth Amendment does not permit the warrantless entry of a home to search a vehicle therein. The constitutional question here is important in its own right, but also because of its implications about the remedies for constitutional violations.

In this case, a police officer—uninvited and without a warrant—walked up the private residential driveway of a home, entered a parking patio, and removed the cover of a parked motorcycle he believed was involved in a past crime. While police generally need a warrant to search a home, they are permitted to search vehicles without a warrant, so long as they have probable cause to believe it contains evidence of a crime. The question, in essence, was which of these doctrines controlled in this case—the warrant requirement or the automobile exception?

In a nearly unanimous opinion by Justice Sotomayor (only Justice Alito dissented), the Court held that this warrantless search was unconstitutional, because the motorcycle was parked in the “curtilage” of the home (i.e., the area immediately surrounding a house, where residents still expect privacy). The Court emphasized that the curtilage is part of the home itself for Fourth Amendment purposes, so the warrant requirement applied in full force. The mere fact that a vehicle may be in the home does not permit a warrantless search, because “the scope of the automobile exception extends no further than the automobile itself.” To get to the motorcycle here, the police officer first had to enter private property that was part of the home, and that initial entry was unlawful without a warrant.

The result in this case is a major vindication of the sanctity of the home for Fourth Amendment purposes. As the Cato Institute emphasized in its amicus brief, “a man’s home is his castle” is not just an aphorism, but an ancient and sacred legal principle. Yet one of the most interesting and potentially significant aspects of this case is not the warrant requirement itself, but the question of remedies—specifically, the intersection of the exclusionary rule and the doctrine of qualified immunity.

Justice Thomas concurred in the Court’s opinion “because it correctly resolves the Fourth Amendment question in this case,” but he wrote separately to express “serious doubts” about applying the exclusionary rule against the states. He stated that “[h]istorically, the only remedies for unconstitutional searches and seizures were ‘tort suits’ and ‘self-help,’” and that “the practice of deterring illegal searches and seizures by suppressing evidence at criminal trials” was unheard of. In his view, even if the federal exclusionary rule is defensible as a kind of federal common law, the rule cannot be applied against the states, because it is not constitutionally mandated by either the Fourth or Fourteenth Amendment.

A Thomas opinion critiquing Supreme Court precedent is always worth a close read, and there is much to recommend to his historical arguments. But his suggestion that Fourth Amendment violations should be addressed through “suits under 42 U.S.C. § 1983” necessarily implicates a separate Supreme Court doctrine that is indisputably without legal or historical support: qualified immunity.

The text of our primary civil rights statute, Section 1983, is plain and straightforward: any state actor who violates someone’s constitutional rights “shall be liable to the party injured.” But under the judge-made doctrine of qualified immunity, public officials are shielded from liability even for illegal misconduct, unless that conduct violated “clearly established law.” This standard is incredibly difficult for plaintiffs to overcome, because courts generally require not just a clear legal rule, but a prior case on the books with functionally identical facts. Judge Lynn Adelman, of the Eastern District of Wisconsin, recently wrote that “[o]f all the restrictions that the Court has imposed on [Section 1983], the one that has rapidly become the most harmful to the enforcement of constitutional rights is the doctrine of qualified immunity.”

Even though the text of Section 1983 says nothing about any immunities, the Supreme Court has claimed that this defense was part of the common law background against which the statute was originally passed. But that assertion is flatly, demonstrably wrong. As Professor William Baude clearly demonstrates in his recent article on the subject, the historical rule was for government agents whose unconstitutional misconduct gave rise to common-law torts was strict liability. In short, the Court’s purported legal basis for this doctrine is just a myth.

So Justice Thomas may be correct that Section 1983 is the proper vehicle for vindicating violations of the Fourth Amendment. But this position presumes that Section 1983 suits are actually a viable means for obtaining relief in such cases—and the Court’s qualified immunity jurisprudence thwarts exactly this aim. The Cato Institute is therefore engaged in an ongoing campaign to challenge the doctrine of qualified immunity, and has filed multiple amicus briefs urging the Supreme Court to reconsider this pernicious doctrine.

To be fair to Justice Thomas, he has also recognized these legal and historical shortcomings of qualified immunity—even citing a pre-publication version of Professor Baude’s article—so he is at least being consistent in his history-based criticisms of the Court’s precedent. But before the Supreme Court even considers revisiting the exclusionary rule, it should first correct the more obviously flawed and actively harmful doctrine of qualified immunity.