In the case of Snepp v. United States (1979), former Central Intelligence Agency (CIA) agent Frank W. Snepp III was sued by the U.S. government for publishing a book about CIA activities in South Vietnam without prepublication review from the agency, which violated his employment agreement with them. The Supreme Court ruled unanimously against Snepp, stating that he had breached a fiduciary duty to respect confidentiality agreements with his employer and thus imposed a "constructive trust" on all profits from his book sales. This meant that any money earned would go directly to the U.S government rather than Snepp himself as punishment for violating this trust relationship between him and the CIA. The court also upheld an injunction preventing him from future publications without prior approval from the agency.

In the dissenting opinion for Snepp v. United States, Justice Stevens argued that the majority's decision was too broad and potentially damaging to First Amendment rights. He contended that while it is important to protect national security secrets, this should not come at the expense of free speech. The court’s ruling allowed for a prior restraint on publication without requiring proof of actual harm or intent to cause harm by Snepp. This could set a dangerous precedent where any former government employee who signs a non-disclosure agreement would be subject to censorship regardless of whether their work actually poses a threat to national security or not. Furthermore, he disagreed with imposing constructive trust as punishment because it seemed more like an attempt by CIA officials seeking revenge rather than protecting state secrets from public exposure.