To protect that right, every unjustifiable intrusion by the Government upon the privacy of the individual, whatever the means employed, must be deemed a violation of the Fourth Amendment.

[4] Until 1914, the American judicial system largely followed the precepts of English common law on matters pertaining to the validity of introducing evidence in criminal trials.

The evidence provided by the wiretapped telephone conversations disclosed "a conspiracy of amazing magnitude" to engage in bootlegging, involving the employment of some fifty persons; with the use of sea vessels for transportation, an underground storage facility in Seattle, and the maintenance of a central office fully equipped with executives, bookkeepers, salesmen, and an attorney.

Taft examined "perhaps the most important" precedent, Weeks v. United States, which involved a conviction for using the mail to transport lottery tickets.

This interpretation complies with the historical purpose of the Fourth Amendment, as it was intended to prevent the use of governmental force to search and seize a citizen’s personal property and effects.

A search and seizure needed to occur physically on the defendants' premises; wiretapping did not because it took place on a publicly-available telephone network that people used voluntarily.

Taft pointed out that one can talk with another at a great distance via telephone, and suggested that because the connecting wires were not in the petitioners’ houses or offices, they could not be subjected to the protections of the Fourth Amendment.

Brandeis noted that the government made no attempt to defend the methods employed by federal agents, and in fact conceded that wiretapping would be unreasonable if it were deemed a search or seizure.

Brandeis concluded that the convictions against Olmstead and the others should be reversed due to the use of inadmissible evidence, while the government had invaded their privacy: “Can it be that the Constitution affords no protection against such invasions of individual security?”[1] Later commentators often made use of Brandeis's statement that "if the government becomes a lawbreaker, it breeds contempt for law; it invites every man to become a law unto himself; it invites anarchy.

[10][11] After his failed appeals, Roy Olmstead spent his 4-year prison sentence at the McNeil Island Correctional Institute in Washington State.

[12] Eventually, Olmstead became a well-known Christian Science practitioner who worked with prison inmates on an anti-alcoholism agenda until his death in 1966 at age 79.