The Fourth Amendment
Freedom from Unreasonable Search and Seizure
The Fourth Amendment to the Constitution guarantees the freedom from unreasonable searches and seizures: 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 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.
What constitutes a search?
Unreasonable search is government interference or invasion where someone has what society deems to be a “reasonable expectation of privacy.” A person’s home, for example, their possessions and their person should be free from government infringement. Courts have determined that there is no reasonable expectation of privacy in such cases as information transmitted to a third party, or trash that is left on the curb outside the area of a home.
Generally, a valid warrant is required for a valid search. There are, however, some exceptions.
First, someone can give valid consent for a search to be conducted. This consent must be entirely voluntary. There is also an “automobile exception” which applies when a car is out on the road, because there a person is considered to have a reduced expectation of privacy (although the contents of the trunk of the car are usually not included in this exception.) There is also an “exigent circumstances” exception, when there is a reasonable belief that evidence is in imminent danger of being removed or destroyed. However, there is a requirement that “probable cause” exist in this case.
Probable cause, in the case of a search, is “a fair probability that contraband or evidence of a crime will be found in a particular place.”
Further exceptions to the warrant rule for searches, based upon what the courts have deemed as “reasonableness,” include searches incident to arrest, protective sweeps, items in plain view and “special needs” searches of workplace documents. Note that there is a diminished reasonable expectation of privacy in the workplace, within certain guidelines in the interest of government efficiency and productivity.
What is a seizure?
For a person: detention by a government official during which one feels one is not free to leave or terminate the encounter.
For property: when there is some meaningful interference/with an individual’s possessory interest in that property.
Probable cause, in the case of detention or arrest of a person, is information that would lead a reasonable person to believe that a crime is about to be or has been committed by the suspect. In such cases, probable cause can be considered a “practical, non technical conception“ based on “common – sense conclusions about human behavior.” For some detentions, “reasonable suspicion,” which is a standard below that of probable cause, can be sufficient. Courts base their decisions on probable cause and reasonable suspicion on the facts and circumstances of the case.
Seizure, again must be based on a valid warrant. However, if evidence is found under a proper exception to the warrant rule for a search, it may be seized.
(It is interesting to note that in a recent Supreme Court case it was determined that the government needs a warrant in order to attach a GPS to someone’s car, because the person has a possessory interest in the car.)