Expectation of privacy
In United States constitutional law the expectation of privacy is a legal test which is crucial in defining the scope of the applicability of the privacy protections of the Fourth Amendment to the United States Constitution. The "expectation of privacy," as a legal concept with a precise definition, is found only in U.S. case law. It is related to, but is not the same thing as a right of privacy, a much broader concept which is found in many legal systems (see privacy law).
There are two types of expectations of privacy:
- A subjective expectation of privacy is an opinion of a person that a certain location or situation is private. These obviously vary greatly from person to person.
- An objective, legitimate or reasonable expectation of privacy is an expectation of privacy generally recognized by society.
Examples of places where a person has a reasonable expectation of privacy are person's residence or hotel room and public places which have been specifically provided by businesses or the public sector to ensure privacy, such as public restrooms, private portions of jailhouses, or a phone booth.
In general, one cannot have an expectation of privacy in public places, with the exceptions mentioned above. A well-known example is denial of privacy for garbage left for collection in a public place.
While a person may have a subjective expectation of privacy in his car, it is not always an objective one, unlike a person's home.
The privacy laws of the United State include the notion of a person's "open fields"; that is, places where a person's possessions do not have an objective expectation of privacy.
Privacy and search
The expectation of privacy is crucial to distinguishing a legitimate, reasonable police search and seizure from an unreasonable one.
In Katz v. United States, Justice John Marshall Harlan II issued a concurring opinion articulating the two-part legal test later adopted by the U.S. Supreme Court as the test for determining whether a police or government search is subject to the limitations of the Fourth Amendment to the United States Constitution: (1) governmental action must contravene an individual's actual, subjective expectation of privacy; (2) and that expectation of privacy must be reasonable, in the sense that society in general would recognize it as such.
To meet the first part of the test, the person from whom the information was obtained must demonstrate that they, in fact, had an actual, subjective expectation that the evidence obtained would not be available to the public. In other words, the person asserting that a search was conducted must show that they kept the evidence in a manner designed to ensure its privacy.
The first part of the test is related to the notion "in plain view". If a person did not undertake reasonable efforts to conceal something from a casual observer (as opposed to a snoop), then no subjective expectation of privacy is assumed.
The second part of the test is analyzed objectively: would society at large deem a person's expectation of privacy to be reasonable? If it is plain that a person did not keep the evidence at issue in a private place, then no search is required to uncover the evidence. For example, there is generally no search when police officers look through garbage because a reasonable person would not expect that items placed in the garbage would necessarily remain private. although the United States Congress has enacted laws that restrict such monitoring. The United States Supreme Court has also ruled that there is no objectively reasonable expectation of privacy (and thus no search) when officers hovering in a helicopter 400 feet above a suspect's house conduct surveillance.