Almost all talk about the law of criminal procedure begins with two assumptions. The first concerns what that law is about. Although the constitutional doctrines that regulate the police protect a number of values or interests, one - privacy - tops the list. The cases and literature on search and seizure, and to a lesser extent on self-incrimination, routinely emphasize the individual's ability to keep some portion of his life secret, at least from the government. That is why Fourth Amendment cases talk about whether evidence is in plain view (and hence no longer hidden from the world(1)) and whether particular places tend to be the locus of activities that most people like to keep secret.(2) That is also why Fifth Amendment cases talk about the defendant's interest in deciding for himself whether to reveal incriminating information; a major underpinning of this "right to choose" is the defendant's interest in keeping the information to himself.(3) Privacy language and privacy arguments are rampant in criminal procedure.(4)
The second assumption usually goes unspoken: criminal procedure, we all suppose, is a self-contained system. It has little or nothing to do with the rest of constitutional law. Constitutional law courses ignore Fourth and Fifth Amendment doctrine, and criminal procedure courses return the compliment; the literatures of criminal procedure and constitutional law do not speak to one another,(5) and the cases do not cite each other. There is a lot to argue about in Fourth and Fifth Amendment law, but the arguments seem to have no effect on debates about the scope of the government's power outside traditionally criminal areas.
These two assumptions cannot stand together. It seems easy and natural to say that we need to protect the individual's interest in keeping some things secret, or at least away from the government's prying eyes, when we regulate the police. Privacy is a comfortable starting point for Fourth and Fifth Amendment law. Yet much of what the modern state does outside of ordinary criminal investigation intrudes on privacy just as much as the kinds of police conduct that Fourth and Fifth Amendment law forbid. A privacy value robust enough to restrain the police should also prevent a great deal of government activity that we take for granted - activity that, at least since the New Deal, is unquestionably constitutional.
To put it differently, a substantive problem lies at the heart. of criminal procedure: the law is grounded on the protection of a particular value, privacy, that implies aggressive substantive judicial review of a sort that we have not allowed for the past half-century. Privacy, at least as the word is used in criminal procedure, protects the interest in keeping information out of the government's hands, and information is necessary to both criminal law enforcement (where aggressive constitutional law is thought to be good) and ordinary regulation (where it is mostly thought to be bad). Criminal procedure, or at least privacy-based criminal procedure, thus has a good deal more substantive bite than we tend to suppose, and its substantive implications push in some uncomfortable directions.
This problem casts fight on a number of features of criminal procedure, both past and present. The idea that the Fourth and Fifth Amendments guarantee broad privacy protection dates back at least to Boyd v. United States,(6) an 1886 Supreme Court decision that laid the foundation for modem search and seizure and self-incrimination doctrine. To modem ears, Boyd sounds like an odd case to lay that foundation: it was a civil forfeiture action arising out of a tax dispute.(7) And Boyd was not unusual in this respect. Case law in the late nineteenth and early twentieth centuries is filled with regulatory disputes - antitrust cases, railroad regulation cases, and the like - in which litigants used the Fourth and Fifth Amendments as shields against government oversight.(8) Yet this civil use of criminal procedure may not be so odd after all. Boyd's broad privacy protection arose around the same time that substantive due process took flight; the substantive implications of Fourth and Fifth Amendment privacy protection may not have seemed as troubling a century ago as they do today. The limits the Court later placed on Boyd's protection may have a great deal to do with changes in the Court's view of those substantive implications.
Broad restraints on government power are more problematic today. Current Fourth and Fifth Amendment law seem's to deal with the problem through a series of special rules or exceptions, doctrines that treat some privacy intrusions as if they just don't count. "Regulatory search" cases allow government searches of businesses with little or no suspicion of misconduct,(9) giving the government much more leeway when enforcing fairly trivial regulations than it has when enforcing laws against rape or murder. "Required records" cases allow the government to compel concededly incriminating disclosures via civil regulatory statutes;(10) once again this doctrine gives the government greater power when enforcing run-of-the-mill regulations than when investigating serious crime. Finally, the "reasonable expectation of privacy" doctrine permits police officers to uncover the details of a suspect's finances(11) or phone calls,(12) even though the same doctrine reaffirms and constitutionally protects the privacy of lunch bags,(13) cigarette packets,(14) and the underside of stereos.(15) No plausible balancing of government need against individual privacy interests can explain these results. Instead, they are best understood as the inevitable consequence of the conflict between privacy-based criminal procedure and the constitutional revolution of the 1930s. In light of that conflict, it is hard to see which side in these disputes is "liberal" and which is "conservative": broader protection of privacy (the supposedly liberal stance) is the road back to the Four Horsemen, while reduced privacy protection (the "conservative" view) guards the integrity of the 1937 revolution.
There are two ways to resolve the tension. The system could protect privacy consistently, across the board. But that course would entail serious costs to the constitutional order under which we have lived since the New Deal: tax forms, OSHA inspections, routine government employment practices, and a host of other things would be constitutionally suspect. The other alternative is to reorient criminal procedure, to focus the law less on privacy and more on what makes the police different from, and more threatening than, the government in its other guises. That task is already underway, though it is mostly implicit. It needs to proceed further, and more candidly.
Part I of this article addresses the connection between privacy-based limits on police authority and substantive limits on government power as a general matter. Part 11 briefly addresses the effects of that connection on Fourth and Fifth Amendment law, both past and present. Part III suggests that privacy protection has a deeper problem: it tends to obscure more serious harms that attend police misconduct, harms that flow not from information disclosure but from the police use of force. The upshot is that criminal procedure would be better off with less attention to privacy, at least as privacy is defined in the doctrine today. Were the law of criminal procedure to focus more on force and coercion and less on information gathering (a change that is already beginning to happen), it would square better with other constitutional law and better protect the interests most people value most highly.
Privacy, Police Investigation, and Substantive
Restraint on Government Power
Criminal procedure is about, as the name says, procedure. One can read widely in the cases and literature without uncovering any indication that restraints on police practices have important substantive effects. Of course, they do. At a broad level, this observation is trite: all procedural rules have substantive effects. But it is useful to see how criminal procedure casts its substantive shadow, and how the size and shape of that shadow depends on the interests the law chooses to protect.
To understand the implications of privacy-based criminal procedure one must start with some conception of privacy. That turns out to be a problem, for the term means too much. In legal discourse privacy encompasses, among other things, the ability to engage in certain conduct free from government regulation,(16) freedom from being stared at or stalked or "singled out" in public,(17) the "right to be let alone,"(18) and the ability to keep certain information or aspects of one's life secret.(19) If one takes privacy to mean all these things, or some fuzzy and varying combination of them, it quickly becomes impossible to say anything useful on the subject. All outcomes make sense on some combination of privacy interests, particularly when one balances them against an equally ill-defined sense of government need.(20)
A more refined definition is needed. In the law of criminal procedure, two kinds of privacy seem to matter. The first is fairly definite: privacy interests as interests in keeping information and activities secret from the government. The focus here is on what government officials can see and hear, what they can find out. The paradigmatic infringement of this kind of privacy is the act of reading someone's correspondence or listening to her telephone conversations, or perhaps rummaging through her bedroom closet. The second kind of privacy is much harder to get one's hands on: it is easier to say what it is not than what it is. It is not, other than coincidentally, about protecting secrets and information. Rather, it is about preventing invasions of dignitary interests, as when a police officer publicly accosts someone and treats him as a suspect. Arrests or...