Constitution protects against illegal searches, Justice Thomas isn’t sure if that’s a good thing

What could possibly go wrong?

CREDIT: Alex Wong/Getty Images
CREDIT: Alex Wong/Getty Images

The Supreme Court held on Tuesday that the Fourth Amendment imposes a narrow but significant limit on police searches. Though cops often have broad authority to search cars, trucks, or motorcycles without obtaining a warrant, Collins v. Virginia holds that police cannot invoke this authority to search a vehicle parked in someone’s driveway.

Though Collins leaves open the possibility that such a warrantless search may be allowed in “exigent circumstances,” Justice Sonia Sotomayor’s opinion for the Court establishes that there are, at least, some constitutional limits on police conduct.

In theory, Justice Clarence Thomas joined Sotomayor’s opinion holding that a person’s home is protected from illegal searches. Yet he also wrote a separate concurring opinion that, if it were embraced by a majority of the Court, would render many police officers virtually immune from constitutional scrutiny.

Thomas would eliminate the most effective mechanism courts have devised to deter police from violating the Constitution. And, in many instances, he would leave criminal suspects with no meaningful protection whatsoever.

One of the backbones of American criminal law is the “exclusionary rule,” which will likely be familiar to anyone who has watched a few episodes of Law and Order. The exclusionary rule provides that, if police seize evidence in searches that violate the Constitution, that evidence typically cannot be used against a criminal defendant in court.


Without such a rule, police would have little incentive to obey the Constitution, as cops could lock up criminal suspects regardless of whether or not they conducted their investigation legally. As the Supreme Court explained more than a century ago, if police are allowed to use illegally obtained evidence, “the protection of the Fourth Amendment declaring [the] right to be secure against such searches and seizures is of no value, and, so far as those thus placed are concerned, might as well be stricken from the Constitution.”

Nevertheless, Thomas writes in his Collins concurrence that he has “serious doubts about this Court’s authority to impose [the exclusionary] rule on the States.” Thomas does not question Sotomayor’s conclusion that police typically need a warrant to enter someone’s driveway, but he would strip away the consequences for many cops who fail to obtain such a warrant.

Under longstanding Supreme Court doctrines, police have “qualified immunity” from suits alleging that they violated the Constitution unless they violate a right that was clearly “established at the time of the alleged violation.” And, even when this qualified immunity can be overcome, many states and localities have indemnity laws which shift the cost of lawsuits challenging police misbehavior from the cops to the taxpayers. According to one study, “governments paid approximately 99.98% of the dollars that plaintiffs recovered in lawsuits alleging civil rights violations by law enforcement.”

Without the exclusionary rule, in other words, police have little incentive to follow the Constitution because they are unlikely to bear the costs of their actions if those actions violate someone’s civil rights.

Thomas’ opinion in Collins rests on a genuine incoherence in the Supreme Court’s Fourth Amendment doctrines. Though the Court held in Mapp v. Ohio that “the exclusionary rule is an essential part of both the Fourth and Fourteenth Amendments,” more recent decisions labeled the exclusionary rule a “‘judicially created remedy‘ of this Court’s own making.”


Thomas’ argument is that the Supreme Court cannot bind state courts unless it does so pursuant to the Constitution or a federal law.

Yet, while that may be true as a general principle, the Court’s decision to divorce the exclusionary rule from its constitutional foundations has less to do with objective legal principles and more to do with the fact that the Court began a 50-year-long drift to the right during the Nixon administration.

The fact remains that, without the exclusionary rule, the Fourth Amendment is likely to become a dead letter.