Olmstead v. United States

Writing for the Court, Chief Justice Taft addressed both of Olmstead's constitutional claims. The Fifth Amendment argument was dismissed outright:

There is no room in the present case for applying the Fifth Amendment, unless the Fourth Amendment was first violated. There was no evidence of compulsion to induce the defendants to talk over their many telephones. They were continually and voluntarily transacting business without knowledge of the interception. Our consideration must be confined to the Fourth Amendment.

The Fourth Amendment, Taft maintained, did not apply in this case either. The government agents investigating the case did not actually invade Olmstead's home, so there could be no question of illegal search and seizure. Somewhat disingenuously, Taft added: "the courts [do not] have a discretion to exclude evidence, the admission of which is not unconstitutional, because unethically obtained."

Writing in dissent, Brandeis argued that, to the contrary, the Fourth and Fifth Amendments, working together, served to protect an implicit right to privacy. It was not necessary for federal agents to trespass physically on the petitioners' property to violate their constitutional rights. Further, Brandeis stated, letting in evidence obtained by wiretapping sanctions criminal behavior on the part of the government.

Later Supreme Court decisions would uphold Brandeis's point of view. The so-called exclusionary rule, prohibiting introduction in criminal trials of illegally obtained evidence, was extended to federal criminal prosecutions in Nardone v. United States (1937). In Katz v. United States (1967), the Court overruled Olmstead outright. Congress, too, passed legislation that outlawed government wiretapping. The 1934 Federal Communications Act prohibited interception of communications, and the Crime Control and Safe Street Act of 1968 permitted the use of wiretaps only when authorized by a federal judge under certain specific circumstances.

Brandeis's advocacy for a right to privacy began with an 1890 law review article in which he and coauthor Samuel Warren posited that although such a right appears nowhere in the Constitution, the nation's foundation document nevertheless supports it. The Supreme Court has rejected the notion Brandeis advanced in Olmstead that invasion of privacy can be a defense in criminal prosecutions. But the Court has endorsed a right to privacy in other areas of the law, most notably with regard to contraception and abortion.