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.