§ 18.01 OVERVIEW

• Jurisdiction: United States

§ 18.01. Overview¹

With one exception,² previous chapters of this text have focused on searches and seizures conducted by police officers in criminal investigations (i.e., in pursuit of criminal evidence; of a person suspected of a crime already committed; or as part of a police effort to investigate crime that may be afoot). In contrast, this chapter centers on searches and seizures, sometimes performed by police officers but often conducted by other public officers, that are ostensibly conducted (at least, primarily) for non-penal, purposes—even if these "non-penal" searches or seizures might later result in criminal prosecutions.

As may be evident from the last sentence, and seen more clearly in later sections of this chapter, the line between a traditional criminal investigation, on the one hand, and a search or seizure designed primarily to serve non-criminal law enforcement goals, on the other hand, is thin and, quite arguably, arbitrary. Yet, it is also a line of considerable constitutional significance.

On the "criminal investigatory" side of the line, the Supreme Court once declared that search warrants, supported by probable cause, were presumptively required. Although warrants today are the exception rather than the rule, they are still required in various situations (e.g., the home), and probable cause remains the touchstone in criminal investigations. Moreover, when probable cause is not required, it remains the case that "[a] search or seizure is ordinarily unreasonable in the absence of individualized [reasonable] suspicion of wrongdoing."³

In contrast, once one moves to the non-criminal investigatory side of the line, the analysis is quite different. Warrants, which are intended for criminal investigations, and "probable cause," which is textually linked to the warrant "requirement," are typically treated as irrelevant. And, the requirement of individualized suspicion of wrongdoing is "not an 'irreducible' component of reasonableness."⁴ Suspicionless, warrantless searches and seizures are frequently permitted in the "non-criminal" realm.

An irony becomes evident once one compares the law on the two sides of the criminal-investigatory line. On the non-criminal law enforcement side of the line, the Supreme Court has often had the opportunity "to hear face-to-face, as Fourth Amendment claimants, those law-abiding citizens for whose ultimate benefit the constitutional restraints on public power were primarily intended."⁵ And yet here the Court...