Potter Stewart

“ No less than an individual in a business office, [10] in a friend's apartment, [11] or in a taxicab, [12] a person in a telephone booth may rely upon the protection of the Fourth Amendment. One who occupies it, shuts the door behind him, and pays the toll that permits him to place a call is surely entitled to assume that the words he utters into the mouthpiece will not be broadcast to the world. To read the Constitution more narrowly is to ignore the vital role that the public telephone has come to play in private communication. ”

“ It is difficult to imagine how any of those exceptions could ever apply to the sort of search and seizure involved in this case. Even electronic surveillance substantially contemporaneous with an individual's arrest could hardly be deemed an 'incident' of that arrest. [20] Nor could the use of electronic surveillance without prior autorization be justified on grounds of 'hot pursuit.' [21] And, of course, the very nature of electronic surveillance precludes its use pursuant to the suspect's consent. ”

“ Once this much is acknowledged, and once it is recognized that the Fourth Amendment protects people and not simply 'areas'-against unreasonable searches and seizures it becomes clear that the reach of that Amendment cannot trun upon the presence or absence of a physical intrusion into any given enclosure. ”