The rights of criminal defendants are protected by the Fourth, Fifth, and Sixth amendments to the Constitution. Although these protections are intended to shield individuals from abuses by the government, the government also has an obligation to safeguard its citizens against criminal activity. The Supreme Court has had to address both concerns.
The Fourth Amendment
The Fourth Amendment is a guarantee against unreasonable searches and seizures and requires that a search warrant be granted only with probable cause. If the police exceed their authority and conduct an illegal search, the evidence gathered may not be admissible in court under what is called the exclusionary rule. While initially applied only to federal cases, the rule has been extended to state courts since 1961. In recent years, the Supreme Court has attempted to limit the exclusionary rule amid complaints that a blanket exclusion of all evidence, used even when the police error was a minor one, was letting guilty defendants go free. Under chief justices Warren Burger and William Rehnquist, the Court has adopted the good faith exception to the Fourth Amendment. This exception uses loopholes in the exclusionary rule, such as when the police believed they had a valid search warrant but it turned out to be based on outdated information. The good faith exception has been applied even to searches without warrants for which the police could show their intention was legal. Warrantless searches are based on a broad interpretation of what constitutes probable cause and a reasonable search. The overall trend has been to weaken the guarantee of personal security in favor of controlling criminal behavior.
The Fifth Amendment
The Fifth Amendment is probably one of the most misunderstood safeguards of personal liberty. In the American legal process, the burden of proof lies with the prosecution; the defendant is innocent until proven guilty and has the right to remain silent. Prosecutors can never ask the accused if he or she committed a crime. Too often, we see through news coverage of actual trials or dramatizations on film or TV someone who is obviously guilty "plead the Fifth." The problem is that such a statement has, for many, come to suggest that the speaker is guilty — the exact opposite of the amendment's intent. To ensure that a person is not made a witness against himself or herself, the Supreme Court has issued several landmark rulings. Escobedo v. Illinois (1964) stated that a person has the right to have an attorney present when questioned by the police. In Miranda v. Arizona (1966), the Court required the police to inform a suspect of his or her constitutional rights. This statement by the police is now known as the Miranda warning.
The Sixth Amendment
The Sixth Amendment deals with the rights of the accused in criminal cases. Although a jury trial is assumed to be a fundamental civil liberty, it was not until 1968 that the Supreme Court ruled that this right is one the states are obligated to recognize in all but the most minor criminal proceedings. The states remain free to set the minimum number of people that constitute a jury, and many do not require a unanimous jury vote for conviction. In Gideon v. Wainright (1963), the Supreme Court held that the right to counsel provided for in the Sixth Amendment extends to the states. The government, at any level, must provide legal assistance to defendants who cannot afford their own lawyer.