In the case of United States v. Zolin et al., 1988, the U.S. Supreme Court addressed whether a court could review documents for attorney-client privilege in response to an IRS summons if there was reasonable cause to believe that they contained evidence of crime or fraud. The Church of Scientology and its lawyers were accused by the Internal Revenue Service (IRS) of tax evasion and fraud, with certain communications between them being subpoenaed as part of this investigation. The defendants argued these communications were protected under attorney-client privilege; however, the government invoked what is known as "crime-fraud exception" which states that such privileges do not apply when legal advice has been sought to further a crime or fraud. The Ninth Circuit ruled against in-camera review (private examination by judge), stating it required prima facie evidence (evidence sufficient at first impression). However, upon appeal, the Supreme Court held that courts can conduct an in-camera review if there's factual basis adequate enough to support good faith belief by a reasonable person for alleged crimes/frauds - thus lowering threshold from prima facie standard set earlier.

In the dissenting opinion for United States v. Zolin et al., Justice Thurgood Marshall, joined by Justice William Brennan, argued that the majority's decision to allow in camera review of potentially privileged attorney-client communications was a significant departure from established legal principles. They contended that such reviews could undermine the sanctity of attorney-client privilege and discourage open communication between attorneys and their clients. The justices also expressed concern about potential abuses of this new power by trial judges who might be tempted to conduct fishing expeditions into confidential materials under the guise of determining whether or not they are privileged. Furthermore, they disagreed with the majority’s assertion that safeguards were in place to prevent misuse because there is no effective way for appellate courts to monitor these proceedings closely enough.