In the case of Carroll et al. v. President and Commissioners of Princess Anne et al., the U.S Supreme Court ruled that a Maryland court's injunction, which prevented a white supremacist group from holding rallies without prior notice to authorities, was unconstitutional as it violated their First Amendment rights to free speech and assembly. The National States' Rights Party had held an initial rally in Princess Anne, Maryland that resulted in violence due to racial tensions. Subsequently, local officials obtained an ex parte order (an action decided by a judge without requiring all parties to be present) barring further gatherings for ten days unless approved by county commissioners or law enforcement agencies. However, the Supreme Court found this preventative measure overly broad and lacking procedural safeguards necessary for restraining free expression - such as prompt judicial review or proof of imminent danger beyond mere speculation.

In the dissenting opinion for Carroll et al. v. President and Commissioners of Princess Anne et al., Justice Black disagreed with the majority's decision to uphold a restraining order against a planned rally by the National States' Rights Party, arguing it violated their First Amendment rights. He contended that while he did not condone or support their message, they had every right to express it under freedom of speech protections in the Constitution. Furthermore, he argued that if there was concern about potential violence at such rallies, then law enforcement should be present to maintain peace rather than suppressing free speech through court orders beforehand based on mere speculation or fear of possible disturbances.