Law enforcement officers are entrusted with the power to conduct investigations, make arrests, perform searches and seizures of persons and their belongings, and occasionally use lethal force in the line of duty. But this power must be exercised within the boundaries of the law, and when police officers exceed those boundaries they jeopardize the admissibility of any evidence collected for prosecution. By and large, the Fourth Amendment and the case law interpreting it establish these boundaries.
The safeguards enumerated by the Fourth Amendment only apply against governmental action, namely action taken by a governmental official or at the direction of a governmental official. Thus, actions taken by state or federal law enforcement officials or private persons working with law enforcement officials will be subject to the strictures of the Fourth Amendment. Bugging, wiretapping, and other related surveillance activity performed by purely private citizens, such as private investigators, will not receive Fourth Amendment protection.
Nor will individuals receive Fourth Amendment protection unless they can demonstrate that they have a reasonable expectation of privacy in the place to be searched or the thing to be seized. The U. S. Supreme Court explained that what “a person knowingly exposes to the public, even in his own home or office, is not a subject of Fourth Amendment protection…. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected” (see Katz v. United States, 389 U.S. 347, 88 S. Ct. 507, 19 L. Ed. 576 ). In general the Court has said that individuals enjoy a reasonable expectation of privacy in their own bodies, personal property, homes, and business offices. Individuals also enjoy a qualified expectation of privacy in their automobiles.
Once it has been established that an individual possesses a reasonable expectation of privacy in a place to be searched or a thing to be seized, the Fourth Amendment’s protections take hold, and the question then becomes what are the nature of those protections. Searches and seizures performed without a warrant (a court order approving a search, a seizure, or an arrest) based on probable cause are presumptively invalid. However, in certain situations the Supreme Court has ruled that warrantless searches may be reasonable under the circumstances and thus pass constitutional muster.
Police officers need no justification to stop some-one on a public street and ask questions, and individuals are completely entitled to refuse to answer any such questions and go about their business. However, the Fourth Amendment prohibits police officers from detaining pedestrians and conducting any kind of search of their clothing without first possessing a reasonable and articulable suspicion that the pedestrians are engaged in criminal activity (see Terry v. Ohio, 392 U.S. 1, 88 S. Ct. 1868, 21 L. Ed. 889 ). Police may not even request that a pedestrian produce identification without first meeting this standard. Similarly, police may not stop motorists without first having a reasonable and articulable suspicion that the driver has violated a traffic law. If a police officer has satisfied this standard in stopping a motorist, the officer may conduct a search of the vehicle’s interior, including the glove compartment, but not the trunk unless the officer has probable cause to believe that it contains contraband or the instrumentalities of criminal activity.
The Fourth Amendment also expresses a preference for arrests to be based on a warrant. But warrantless arrests can be made when the circumstances make it reasonable to do so. For example, no warrant is required for a felony arrest in a public place, even if the arresting officer had ample time to procure a warrant, so long as the officer possessed probable cause that the suspect committed the crime. Felony arrests in places not open to the public generally do require a warrant, unless the officer is in “hot pursuit” of a fleeing felon (see Warden v. Hayden, 387 U.S. 294, 87 S.Ct. 1642, 18 L.Ed.2d 782 ). The Fourth Amendment also allows warrantless arrests for misdemeanors committed in an officer’s presence.
The exceptions to the Fourth Amendment’s warrant requirement are based on the court’s reluctance to unduly impede the job of law enforcement officials. Courts attempt to strike a balance between the practical realities of daily police work and the privacy and freedom interests of the public. Requiring police officers to take the time to obtain an arrest or search warrant could result in the destruction of evidence, the disappearance of suspects, or both.
When an officer does seek a search or arrest warrant, the officer must present evidence to a neutral judge or magistrate sufficient to establish probable cause that a crime has been committed. The Supreme Court has said that probable cause exists when the facts within an officer’s knowledge provide a reasonably trustworthy basis for a man of reasonable caution to believe that an offense has been committed or is about to be committed. Courts will deny requests when the warrant fails to describe in particularized detail the person to be arrested or the place to be searched. The evidence upon which a warrant is based need not be ultimately admissible at trial, but it cannot be based on knowingly or intentionally false statements or statements made in reckless disregard of the truth. Courts will usually invalidate searches, seizures, and arrests made pursuant to a defective warrant. Inaccuracies found in a warrant due to ordinary negligence will not typically jeopardize a warrant’s validity.