In the case of Central Intelligence Agency et al. v. Sims et al., 1984, the U.S Supreme Court ruled in favor of the CIA, upholding its right to withhold names and other identifying details about individuals involved in a covert research program (Project MKUltra) from public disclosure under Freedom of Information Act requests. The court held that such information fell within an exemption designed to protect intelligence sources and methods from unauthorized disclosure. The plaintiffs had argued that this exemption should be narrowly interpreted to only cover paid informants or employees who could face retaliation if their identities were revealed but not researchers or institutions engaged by contract with the agency for scientific research purposes. However, writing for a majority on the bench, Justice William Rehnquist rejected this interpretation as too narrow and potentially harmful to national security interests.

In the dissenting opinion for the Central Intelligence Agency et al. v. Sims et al., Justice Brennan, joined by Justices Marshall and Blackmun, argued that the majority's interpretation of "intelligence sources" was overly broad and not in line with congressional intent when it enacted the Freedom of Information Act (FOIA). They contended that such a wide definition would allow almost any information to be withheld from public access if it were related to intelligence activities. The dissenting justices believed this contradicted FOIA’s purpose: promoting transparency in government operations. Furthermore, they expressed concern about leaving determinations on what constitutes an "intelligence source" solely up to CIA officials without judicial review or oversight as this could lead to potential abuses of power.