The Supreme Court Fails the Fourth Amendment Test

What all the justices don’t understand about police investigations.

A TSA agent waits for passengers to use the TSA PreCheck lane being implemented by the Transportation Security Administration at Miami International Airport on October 4, 2011 in Miami, Florida.

Airport screening is an entirely different category of “search” than post-arrest DNA swabbing

Joe Raedle/Getty Images

At argument, Justice Samuel Alito called Maryland v. King, in which the Supreme Court just ruled that states may collect DNA from people when they are arrested, “perhaps the most important criminal procedure case that this Court has heard in decades.” He’s right, and too bad for the rest of us. When Tea Party Sen. Ted Cruz and the New York Times both conclude that a decision was wrong-headed, and when the American Prospect and the Committee for Justice nod in agreement, you can be pretty sure the Supreme Court’s choo-choo has gone off the rails. The dispute between Justice Anthony Kennedy, writing for a majority of five, and Justice Antonin Scalia, dissenting for the other four, will have ramifications far beyond DNA testing, affecting much of policing in the 21st century. Unfortunately, neither of them got it quite right.

Alonzo King was arrested in 2009 for pulling a shotgun on some people. Following a Maryland law, the police swabbed his cheek for his DNA. When that sample was matched against the FBI’s DNA database, King came up as the suspect in a cold rape case from six years earlier. He was found guilty.

Justice Scalia had a sharp answer to the majority’s assertion that DNA testing of all arrestees for “serious” crimes (whatever those are) is OK:

“The Fourth Amendment forbids searching a person for evidence of a crime when there is no basis for believing the person is guilty of the crime or is in possession of incriminating evidence. That prohibition is categorical and without exception; it lies at the very heart of the Fourth Amendment.”

That bold clarity is characteristically Scalia; it’s also wrong. As Justice Kennedy made clear, we allow all sorts of searches without cause. When the police make an arrest, they can search for weapons without any reason to believe the person is carrying one, on the assumption that it’s too dangerous to risk taking someone into custody with a gun. Ditto fingerprinting: It is important to identify the arrested person, even if there is no cause to think they are hiding their identity.

But the problem of whether to allow searches without probable cause goes way beyond the procedures surrounding arrest, and has given the justices fits in a variety of circumstances. Think of airport security or drunk-driving roadblocks. There’s no probable cause to think any given person in those situations has violated the law, but no one believes they are unconstitutional. The question is, why not?

In a series of cases, the Supreme Court has concluded that searches without probable cause are lawful if the government has “special needs,” and if the “primary purpose” of the search is not collecting evidence for ordinary law enforcement. Citing special needs, the justices and the lower courts have upheld a plethora of practices, from drunk-driving roadblocks, to drug testing of students and transportation workers.

The problem here is that the justices are doing the equivalent of asking if a turkey is an animal native to North America or food for Thanksgiving. It’s both. Do we have drunk-driving roadblocks to deter people from drunk driving or to get evidence to convict those who are actually driving drunk? Yes.

Maryland v. King gave the justices a chance to clear up the confusion, and they all blew it. Justice Scalia bought into the meaningless turkey distinction when he wrote, “Whenever this Court has allowed a suspicionless search, it has insisted upon a justifying motive apart from the investigation of a crime.” Justice Kennedy ultimately ducked the turkey inquiry. After trying unsuccessfully to argue that the purpose of searching King was not to investigate cold cases, but to identify him, he concluded it didn’t matter anyway because arrestees have a “reduced expectation of privacy.”

What the justices seem to see only through a glass darkly is that there are two very different kinds of searches, reflecting two different kinds of policing. There are investigative searches, and there are regulatory searches. The first kind are what you see on television, like on The Closer when Brenda Leigh Johnson tries to catch a bad guy who has committed or is about to commit a crime. The second kind includes airport security or drunk driving roadblocks—or even searching arrested people for weapons. These searches aim not to catch criminals, but to deter bad things from happening in the first place. Sure, we want to find the person getting on a plane with a gun. But the real reason for airport security is to deter people from bringing weapons to airports in the first place.

The categories matter because until you see them you can’t understand what the Fourth Amendment’s protection against unreasonable search and seizure offers in each situation. Justice Scalia was right that the Fourth Amendment is categorical in requiring that the police must have a good reason before conducting investigative searches. These searches target a specific person for a specific crime, and before the government can single you out from the crowd for its special, loving attention, it has to have reason to believe you deserve to be the lucky winner. That’s probable cause.

If you think about it for all of a nanosecond, though, it makes zero sense to talk about “probable cause” as a protection against regulatory, deterrent searches. We don’t have any reason to think anyone in the airport security line did anything wrong. But does that mean airport security is unconstitutional? Surely not!

The Constitution does offer protection from invalid regulatory searches, though, in two ways. The first is generality: Search everyone, and there is a good chance the courts should uphold it. If Congress decided that everyone in the country, members of Congress included, should be in the DNA databank, lawmakers are more likely to have a good reason than if they only go after a politically vulnerable group like people who are arrested. (And yes, the chance of universal DNA collection actually getting adopted by Congress resembles that of the proverbial snowball surviving in Hades, demonstrating how general applicability is a good political check on government intrusiveness.)

The second protection is “cause,” but of a specific and heightened sort: The rule should be that the government must have a really, really good reason to subject a particular group to a regulatory search—for example to collect DNA from arrestees rather than from everyone. The DNA test of King couldn’t survive as an investigative search because there was no reason to believe, at the time his cheek was swabbed, that he’d committed the rape for which he ultimately was convicted. Could the DNA collection be justified on a regulatory basis? The right question is this: Did the fact that Alonzo King was accused (not convicted) of pulling a shotgun on some folks provide a better reason to believe he’d committed an unrelated rape than that anyone else walking the streets had done so? Hardly. And that is why the justices got Maryland v. King wrong.