Olmstead v. United States, 277 U.S. 438 (1928)
"The
makers of our Constitution undertook to secure conditions favorable
to the pursuit of happiness. They recognized the significance of man's
spiritual nature, of his feelings and of his intellect. They knew that
only a part of the pain, pleasure and satisfactions of life are to be
found in material things. They sought to protect Americans in their
beliefs, their thoughts, their emotions and their sensations. They conferred,
as against the Government, the right to be let alone - the most comprehensive
of rights and the right most valued by civilized men. To protect that
right, every unjustifiable intrusion by the Government upon the privacy
of the [468 U.S. 517,
557] individual, by whatever the means employed, must
be deemed a violation of the Fourth Amendment." Olmstead v. United States,
277 U.S. 438, 478 (1928) (Brandeis, J., dissenting).
[Olmstead
v. United States, 277 U.S. 438 (1928)]
"Even if we direct our attention to the
original checks and deposit slips, rather than to the microfilm
copies actually viewed and obtained by means of the subpoena, we
perceive no legitimate "expectation of privacy" in their contents.
The checks are not confidential communications but negotiable instruments
to be used in commercial transactions. All of the documents obtained,
including financial statements and deposit slips, contain only information
voluntarily conveyed to the banks and exposed to their employees
in the ordinary course of business. The lack of any legitimate expectation
of privacy concerning the information kept in bank records was assumed
by Congress in enacting the Bank Secrecy Act, the expressed purpose
of which is to require records [425 U.S. 435, 443] to be maintained
because they "have a high degree of usefulness in criminal, tax,
and regulatory investigations and proceedings." 12 U.S.C. 1829b
(a) (1). Cf. Couch v. United States, supra, at 335.
"The depositor takes the risk, in revealing
his affairs to another, that the information will be conveyed by
that person to the Government. United States v. White, 401 U.S.
745, 751 -752 (1971). This Court has held repeatedly that the Fourth
Amendment does not prohibit the obtaining of information revealed
to a third party and conveyed by him to Government authorities,
even if the information is revealed on the assumption that it will
be used only for a limited purpose and the confidence placed in
the third party will not be betrayed. Id., at 752; Hoffa v. United
States, 385 U.S., at 302 ; Lopez v. United States, 373 U.S. 427
(1963). 4 "
United States vs Miller, 425 US 435 (1976)[]