The Fourth Amendment, and the personal rights which it secures, have a long history. At the very core stands the right of a man to retreat into his own home and there be free from unreasonable governmental intrusion.

Potter Stewart (1915-1985) US Supreme Court Justice (1959-81)

Silverman v. United States, 365 U.S. 505 (1961) [Unanimous opinion]
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Note that the quote is frequently misidentified as being from Katz v. United States or Bartkus v. Illinois.