3A- 4- The Fourth Amendment

Warrantless Search

A warrantless search is presumptively unreasonable—and, therefore, a violation of the Fourth Amendment. A warrant may issue only if the government establishes that "probable cause" exists that a crime has been committed, is being committed, or is likely to be committed. There are a number of important exceptions to this rule, including an exception for evidence found in "plain view." The full scope of Fourth Amendment exceptions, however, are outside the scope of the CIPP/US Exam.

Initial interpretation of fourth Amendment by SCOTUS

As initially interpreted by the United States Supreme Court, the Fourth Amendment protected against physical intrusion. This understanding led the court to hold in Olmstead v. United States, that the Fourth Amendment did not require that a warrant be issued in order to conduct a wiretap.

Fourth Amendment applicability when information is disclosed to a third party

Because protection under the Fourth Amendment is premised upon privacy interests, if information is disclosed to a third party, the Fourth Amendment does not protect it from disclosure. "What a person knowingly exposes to the public, even in his own home or office, is not subject of Fourth Amendment protection."For this reason, many records that individuals consider private in nature—for example, those records disclosed to a financial institution—are not subject to Fourth Amendment protections. It follows, then, that organizations are free to turn over information about customers and employees to law enforcement without the government running afoul of the Constitution. This is a particularly important consideration when discussing workplace privacy, which will be covered later in this study guide.

Even where the Fourth Amendment does apply, it sets only a minimum standard that law enforcement officials must satisfy in order to obtain access to private communications.

Even where the Fourth Amendment does not limit access to personal information, other restrictions set forth by statute may prohibit the disclosure of information to law enforcement. The restrictions under the Right to Financial Privacy Act provide a good example. Moreover, even where the Fourth Amendment does apply, it sets only a minimum standard that law enforcement officials must satisfy in order to obtain access to private communications. Congress (and state legislatures) are free to set a higher standard for law enforcement officials to obtain access to certain types of communications. Congress has done this with respect to wiretaps, emails, stored records, and pen registers.

There have been several important, recent changes in the SCOTUS's Fourth Amendment jurisprudence.

First, in United States v. Jones, the Court held that attaching a GPS device on a car and tracking the car over a period of a month was a violation of the Fourth Amendment. The majority opinion relied on the fact that the police trespassed upon the car to support its decision. Four justices in a concurring opinion, however, would have held that a Fourth Amendment "search" occurred even without the physical intrusion on the vehicle. Two years later, in Riley v. California, the Court unanimously held that a cell phone cannot be searched without a warrant because the amount of information on the phone was both quantitatively and qualitatively different than what is in a physical container. Both of these cases indicate that the court now considers the quantity of information and the level of invasiveness to be important considerations for determining whether the Fourth Amendment applies. This change in understanding harkens back to a famous line by Justice Louis Brandeis in his dissenting opinion in Olmstead, where he stated that the Fourth Amendment must have the "capacity of adaptation to a changing world."

Exclusionary Rule

Pursuant to what is referred to as the Exclusionary Rule, evidence that is obtained in violation of the Fourth Amendment is prohibited from being introduced as evidence during a criminal trial. As a corollary to this rule, the Fruit of the Poisonous Tree Doctrine provides that if evidence that is obtained in violation of the Fourth Amendment leads to the discovery of additional evidence against a criminal defendant, that additional evidence is also subject to the Exclusionary Rule and may not be introduced at trial. These rules help undermine any incentive law enforcement may have to disregard the Fourth Amendment's protections in order to obtain a conviction.

Since Katz, the protections under the Fourth Amendment have been understood to be premised upon "a reasonable expectation of privacy."

Since Katz, the protections under the Fourth Amendment have been understood to be premised upon "a reasonable expectation of privacy." This applies to both physical premises and private conversations. Under this test, in order for the Fourth Amendment to apply, a person must have a subjective intent to keep the conversation private and the expectation must be one "that society is prepared to recognize as 'reasonable.'"

SCOTUS's understanding of the Fourth Amendment changed, in the 1960s:

The Court's understanding of the Fourth Amendment changed, however, in the 1960s. In 1967, the Court effectively overruled Olmstead in the case Katz v. United States, where it found that a warrant was needed for police to place a "bug" in a restaurant.3 In that case, the Court stated that what a person "seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected" under the Fourth Amendment.

Key Points

The Fourth Amendment prevents unreasonable searches and seizures The Fourth Amendment applies based upon whether a person has "a reasonable expectation of privacy" in what is being searched or seized; this includes both a subjective and objective component A warrantless search is presumptively unreasonable, but there are many exceptions to this rule (e.g., the "plain view" exception) Exclusionary Rule: Evidence that is obtained in violation of the Fourth Amendment is prohibited from being introduced as evidence during a criminal trial Fruit of the Poisonous Tree Doctrine: if evidence that is obtained in violation of the Fourth Amendment leads to the discovery of additional evidence against a criminal defendant, that additional evidence is also subject to the Exclusionary Rule The Fourth Amendment only sets a floor; statutes can provide greater protection

The Fourth Amendment to the United States Constitution States:

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 and affirmation, and particularly describing the place to be searched.