At the height of our last war on drugs—Prohibition, in the late 1920s—the federal government began using a technique of police work that startled many but proved quite effective. The technique was wiretapping.¹ Telephones had become a dominant mode of communication, life had just begun to move onto the wires, and in an effort to take advantage of the evidence that this new medium might yield, the government, without warrants, began to tap phones.

Because law enforcement officials themselves were conflicted about the ethics of wiretapping, taps were used sparingly. Nonetheless, for threats perceived to be extremely grave, the technique was deployed. Illegal alcohol, as the obsession of the age, was just such a threat.

The most famous of these taps led to the 1928 Supreme Court case Olmstead v United States. The government was investigating one of the largest illegal liquor import, distribution, and sales organizations in the nation. As part of the investigation, the government began to tap the telephones used by dealers and their agents. These were private phones, but the taps were always secured without trespassing on the property of the targets.² Instead, the taps were placed on the wires in places where the government had rightful access to the phone lines. Though wiretapping was illegal under many states’ laws, the government had not illegally trespassed on the defendants’ property while tapping phones.

Using these taps, the government recorded many hours of conversations (775 typewritten pages, according to Justice Louis Brandeis’s dissent)³ , and it used these recordings to convict the defendants in the case. The defendants challenged the use of these recordings, claiming that the government had violated the Constitution in securing them. The Fourth Amendment protects “persons, houses, papers, and effects, against unreasonable searches and seizures,” and this wiretapping, the defendants argued, was a violation of their right to be protected from unreasonable searches.

Under then-existing law, it was plain that to enter the apartments of Mr. Olmstead and his accomplices and search them (at least while they were gone), the government investigators would have needed a warrant, that is, they would have needed the approval of a judge or magistrate before invading the defendants’ privacy. This is what the Fourth Amendment had come to mean—that certain places (persons, houses, papers, and effects) were protected by presumptively requiring a warrant before they could be invaded.⁴ Here there had been no warrant, and hence, as the defendants argued, the search had been illegal. The evidence had to be excluded.

We might pause to ask why. If we read the text of the Fourth Amendment carefully, it is hard to see just where a warrant is required:

(a) The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and (b) no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

The Fourth Amendment is really two commands. (I’ve added “a” and “b” to help make the point.) The first says that a certain right (“the right of the People to be secure”) shall not be violated; the second limits the conditions under which a warrant shall be issued. But the text of the amendment does not state a relationship between the first part and the second part. And it certainly does not say that a search is unreasonable if it is not supported by a warrant. So why “the warrant requirement”?⁵

To make sense of the amendment, we must go back to its framing. At that time, the legal protection against the invasion of privacy was trespass law. If someone entered your property and rifled through your stuff, that person violated your common law rights against trespass. You could sue that person for trespass, whether he was a police officer or private citizen. The threat of such suits gave the police an incentive not to invade your privacy.⁶

Even without a warrant, however, a trespassing police officer might have a number of defenses. These boil down to whether the search was “reasonable.” But there were two important facts about this reasonableness. First, the determination of reasonableness was made by a jury. Neighbors and peers of the officer judged whether his behavior had been proper. Second, in some cases reasonableness was found as a matter of law—that is, the judge would instruct the jury to find that the search had been reasonable. (For example, when the officer found contraband on the property of the defendant, whether there was sufficient suspicion before the search or not, the search was reasonable.)⁷

This regime created obvious risks for an officer before he searched someone’s property. If he searched and found nothing, or if a jury thought later that his search had not been reasonable, then he paid for his illegal behavior by being held personally liable for the rights he had violated.

Footnotes

¹ Justice Holmes himself called the wiretapping a “dirty business”; Olmstead v United States, 277 US 438, 470 (1928) (Justice Oliver Wendell Holmes Jr. dissenting). Edit Delete

² Ibid., 457 (Chief Justice William H. Taft: the obtaining of evidence by wiretaps inserted along telephone wires was done without trespass and thus did not violate the Fourth Amendment). Edit Delete

³ Ibid., 471 (Justice Louis D. Brandeis dissenting; Justices Holmes, Stone, and Butler also filed dissents). Edit Delete

⁴ There is an extensive debate about the original meaning of the Fourth Amendment and how it should be applied today. For the two camps, see Akhil Reed Amar, “Fourth Amendment First Principles,” Harvard Law Review 107 (1994): 757; Tracey Maclin, “The Complexity of the Fourth Amendment: A Historical Review,” Boston University Law Review 77 (1997): 925 (critiquing Amar’s argument). Edit Delete

⁵ See California v Acevedo, 500 US 565, 582 (1991) (Justice Antonin Scalia concurring: describing warrant requirement as “riddled with exceptions”). Edit Delete

⁶ See Bradford P. Wilson, “The Fourth Amendment as More Than a Form of Words: The View from the Founding,” in The Bill of Rights: Original Meaning and Current Understanding, edited by Eugene W. Hickok Jr. (Charlottesville: University Press of Virginia, 1991), 151, 156–57. As many have pointed out, there were not really any “police” at that time in the sense that we understand the term today. The modern police force is a creation of the nineteenth century; see Carol S. Steiker, “Second Thoughts About First Principles,” Harvard Law Review 107 (1994): 820, 830–34; Stuntz, “The Substantive Origins of Criminal Procedure.” Edit Delete

⁷ See Amar, “Fourth Amendment First Principles,” 767; Stuntz, “The Substantive Origins of Criminal Procedure,” 400. Edit Delete