(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.
But the regime also offered insurance against this liability — the warrant. If the officer secured a warrant from a judge before he made his search, the warrant immunized him against trespass liability. If he then found no contraband or his search turned out to be unreasonable, he still had a defense to a suit.
Creating incentives was one aim of the original system. The law gave an officer an incentive to obtain a warrant before he searched; if he was uncertain, or wanted to avoid all risk of liability, he could first check his judgment by asking a judge. But if the officer was sure, or wanted to hazard the gamble, then not getting a warrant did not make the search automatically unreasonable. He was at risk of increased liability, but his liability was all that was at stake.
The weak link in this system was the judge. If judges were too lax, then warrants would be too easy to get[8], and weak judges were a concern for the framers. Under British rule judges had been appointed by the Crown, and by the time of the Revolution, the Crown was the enemy. Having seen much abuse of the power to issue warrants, the framers were not keen to give judges control in determining whether the government’s searches were reasonable.
In particular (as I described in Chapter 2), the framers had in mind some famous cases in which judges and the executive had issued “general warrants” giving government officers the power to search generally for objects of contraband[9]. In modern terms, these were “fishing expeditions.” Because the officers had warrants, they could not be sued; because the judges were largely immune from suit, they could not be sued. Because no one could be sued, there was a temptation for abuse. The framers wanted to avoid just such judge-made abuse. If there was to be immunity, it would come from a jury, or from a successful search.
This is the origin of clause (b) of the Fourth Amendment. The framers required that judges, when issuing warrants, name particularly “the place to be searched, and the persons or things to be seized”, so that judges would not be able to issue warrants of general power. The immunity of the warrant would be limited to particular people and places, and only when probable cause existed to issue the warrant.
This constitutional regime was designed to balance the people’s interests in privacy against the legitimate need for the government to search. The officer had an incentive to get a warrant (to avoid the risk of personal liability); the judge had a rule that restricted the conditions under which he could issue a warrant; and together these structures limited official invasions of privacy to cases that presented a strong reason to invade.
That much is background. But notice what follows.
The original regime presupposed a great deal. Most obviously, it presupposed a common-law system of trespass law — it was the threat of legal liability from trespass law that created the incentives for officers to seek warrants in the first place. This presupposition placed property at the core of the Constitution’s original protections.
Equally important, the regime presupposed much about the technology of the time. The Fourth Amendment focuses on trespass because that was the primary mode of searching at the time. If it had been possible simply to view the contents of a house without going inside, the restrictions of the Fourth Amendment would have made little sense. But the protections of the amendment did make sense as a way to draw the balance between government’s power to search and the people’s right to privacy given the regime of trespass law and privacy-invading technologies that prevailed at the end of the eighteenth century.
Presuppositions — what is taken for granted or considered undebatable — change[10]. How do we respond when such presuppositions change? How do we read a text written against a background of certain presuppositions when those presuppositions no longer apply?
For Americans, or for any nation with a constitution some two hundred years old, this is the central problem for constitutional interpretation. What if state governments, for example, were simply to abolish rights against trespass? Would the amendment be read any differently[11] ? What if technologies for searching were to change so dramatically that no one would ever need to enter another’s property to know what is kept there? Should the amendment then be read differently?
The history of the Supreme Court’s treatment of such questions lacks a perfectly clear pattern, but we can identify two distinct strategies competing for the Court’s attention. One strategy is focused on what the framers or founders would have done — the strategy of one-step originalism. The second strategy aims at finding a current reading of the original Constitution that preserves its original meaning in the present context — a strategy that I call translation.
Both strategies are present in the Olmstead wiretapping case. When the government tapped the phones of the defendants without any warrant, the Court had to decide whether the use of this kind of evidence was permissible or consistent with the principles of the Fourth Amendment. The defendants said: The government must
