Questions involving the protections of the 4th Amendment for persons in their home were not new to the Supreme Court. In cases such as Weeks, 1914, and Mapp, 1961, the Court examined the meaning of the security of the home. The Court ruled that a faulty warrant—or no warrant at all—would generally result in the exclusion of evidence, gained in violation of a citizen's due process rights, from trials in both State and federal courts. Later decisions (Sheppard, 1966, Leon, 1984, Nix, 1984) narrowed the protections against unreasonable searches based on faulty warrants. However, until this case came before the Court, no significant modifications to the exclusionary rule had occurred regarding searches of a home or the "home area" without a warrant.
Was a person protected against searches without a warrant when the person was away from home? Were there "places"—that is, the "home area," or as in Katz, 1967, a phone booth—that were protected from "unreasonable searches and seizures" by the 4th Amendment, or was it "the citizen" who was protected? In the wiretapping case Katz v. United States, 1967, the Court said that "what a person knowingly exposes to the public, even in his own home or office, is not a subject of 4th Amendment protection…. But what he seeks to preserve as private, even in an area accessible to the public [emphasis added], may be constitutionally protected." The question of where a "reasonable expectation of privacy" ended, as the concept was expressed in Katz, required additional examination by the Court.
After learning from an informant that Billy Greenwood of Laguna Beach, California, might be trafficking in drugs, police investigator Jenny Jones observed several cars making brief nighttime stops at Greenwood's expensive home. Jones asked the local refuse collector to turn over Greenwood's brown plastic trash bags to police after the collector had picked up the trash at the Greenwood residence. Investigator Jones, however, had never filed for a warrant to conduct this "search."
Police examined the trash bags in detail and discovered a variety of drug-related items. A warrant was then obtained to search Greenwood's home, where police found cocaine and hashish. Greenwood was taken into custody.
Greenwood and an alleged accomplice were prosecuted, but a California State court of appeals dismissed the charge against Greenwood, citing State court precedents and previous Supreme Court rulings against the admission of evidence obtained in such a way. After the Supreme Court of California upheld the finding of the appeals court, the State of California appealed the case to the Supreme Court.
The case involved the protections extended by the 4th Amendment and the limits of the exclusionary rule. What is the extent of a person's "penumbra of privacy"? When does a person's trash become "public property"? Is trash protected after it has been taken out of a person's home to a trashcan behind the home? Is it protected at the curb? Does a person's "penumbra of privacy" reach all the way to the trash dump? Can a person have a "reasonable expectation of privacy" for material exposed to public view at the curb? Can evidence gained from a trash bag at the curb be used as "probable cause" for a warrant?
For the State of California: The trash at the curb is outside the "curtilage," or area of reasonable control, of the homeowner. It is not within the protection of the 4th Amendment, for any passerby could have access to it. The Mapp rule dealt with searches inside a building and is not applicable to this case. No one has an "expectation of privacy" when he or she has relinquished effective control of the trash by putting it out for collection. The trash was released for public view by the defendant. It provided "adequate probable cause" for the warrant to search the home, and the evidence gained by that search is admissible as part of the prosecution's case for illegal drug trafficking.
For Greenwood: California officers lacked "adequate probable cause" to search the trash; thus, that evidence should not be admissible. Without the evidence gathered through the search of the trash, police would have had no probable cause for the warrant to search the home. Therefore, the warrant and the evidence gathered should both be found inadmissible. There was not consent by the defendant to any search, and the defendant had "reasonable expectation of privacy" regarding his trash when it was put out for the trash collector. The search warrant was faulty because the evidence used to substantiate the warrant was illegally gained. The evidence gained from the house search should not be admitted to prosecution.
Justice Byron White wrote the majority opinion for the court in its 6–2 decision, and without Justice Kennedy's participation. The Court held that the 4th Amendment does not prohibit the search and seizure, without a warrant, of garbage that is left for collection "outside the curtilage of a home."
White wrote, "It is common knowledge that plastic garbage bags left on or at the side of a public street are readily accessible to animals, children, scavengers, snoops and other members of the public." Requiring a warrant to search an area to which the public has easy access is inappropriate and unnecessary.
Justices Brennan and Marshall responded in a strong dissent saying that "members of our society will be shocked" by the decision. "Scrutiny of another's trash is contrary to commonly accepted notions of civilized behavior…. A single bag of trash testifies eloquently to the eating, reading and recreational habits of the person who produced it…. Trash bags can relate intimate details such as professional status, political inclinations, private thoughts, personal relationships and romantic interests…." With its Greenwood decision, the Court continued to take a narrow view of the "right to privacy."
Some legal observers are concerned by this trend. "The message [of the decision] is: Be careful of what you put in the garbage," observed Professor Graham Hughes of New York University Law School. Arthur Spitzer of the American Civil Liberties Union commented that the decision "is one more step in squeezing the right to privacy to the point where Americans will no longer feel secure against the prying eye of Big Brother…."