In the United States v. Miller case of 1975, the Supreme Court ruled on issues related to bank secrecy and privacy rights. The defendant, Mitch Miller, was under investigation by law enforcement for alleged illegal gambling activities. As part of their investigation, they subpoenaed his bank records without his knowledge or consent. Miller argued that this violated his Fourth Amendment right against unreasonable searches and seizures as well as his Fifth Amendment right against self-incrimination. However, the court disagreed with him in a unanimous decision stating that individuals do not have an expectation of privacy regarding their banking transactions because these are business records owned by the banks themselves rather than personal papers protected by constitutional rights to privacy.

In the dissenting opinion for United States v. Miller, Justice Brennan argued that the majority's decision failed to adequately protect an individual's right to privacy under the Fourth Amendment. He contended that bank records should be considered private and personal documents, even if they are held by a third party like a bank. In his view, individuals do not forfeit their expectation of privacy simply because they choose to conduct their financial affairs through a bank. Furthermore, he disagreed with the majority’s assertion that checks and deposit slips were not confidential since these items reveal intimate details about an individual’s life such as political contributions or medical expenses which could potentially be used against them in criminal proceedings without proper safeguards in place.