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Silverman v. United States, 365 U.S. 505 (1961) (full-text).

U.S. Supreme Court Proceedings[]

In Silverman, the U.S. Supreme Court held that the Fourth Amendment prohibited the government’s physical intrusion upon private property during an investigation when government agents drove a “spike mike” into the common wall of a row house until it made contact with a heating duct for the home in which the conversation occurred.

Silverman presented something of a technical problem, because there was some question whether the spike mike had actually crossed the property line of the defendant’s town house when it made contact with the heating duct. The Court declined to rest its decision on the technicalities of local property law, and instead found that the government’s conduct had intruded upon privacy of home and hearth in a manner condemned by the Fourth Amendment.[1] The Court stated:

The absence of a physical invasion of the petitioner’s premises was also a vital factor in the Court’s decision in Olmstead v. United States . . . . In holding that the wiretapping there did not violate the Fourth Amendment, the Court noted that the insertions were made without trespass upon any property of the defendants. They were made in the basement of the large office building. The taps from house lines were made in the streets near the houses. 277 U.S. at 457. There was no entry of the houses or offices of the defendants. Id. at 464. Relying upon these circumstances, the Court reasoned that the intervening wires are not part of (the defendant’s) house or office any more than are the highways along which they are stretched. Id. at 465.

Here, by contrast, the officers overheard the petitioners’ conversations only by usurping part of the petitioners’ house or office — a heating system which was an integral part of the premises occupied by the petitioners, a usurpation that was effected without their knowledge and without their consent. In these circumstances we need not pause to consider whether or not there was a technical trespass under the local property law relating to party walls. Inherent Fourth Amendment rights are not inevitably measurable in terms of ancient niceties of tort or real property law . . . .

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. . . . This Court has never held that a federal officer may without warrant and without consent physically entrench into a man’s office or home, there secretly observe or listen, and relate at the man’s subsequent criminal trial what was seen or heard.

A distinction between the dictaphone employed in Goldman [Goldman v. United States], 316 U.S. 129 (1942)] and the spike mike utilized here seemed to the Court of Appeals too fine a one to draw. The court was unwilling to believe that the respective rights are to be measured in fractions of inches. But decision here does not turn upon the technicality of a trespass upon a party wall as a matter of local law. It is based upon the reality of an actual intrusion into a constitutionally protected area. What the Court said long ago bears repeating now: It may be that it is the obnoxious thing in its mildest and least repulsive form; but illegitimate and unconstitutional practices get their first footing in that way, namely, by silent approaches and slight deviations from legal modes of procedure. Boyd v. United States, 116 U.S. 616, 635. We find no occasion to re-examine Goldman here, but we decline to go beyond it, by even a fraction of an inch.[2]


  1. 365 U.S. at 510-12.
  2. Id. at 510-12 (internal quotation marks omitted).