In Noto v. United States, the Supreme Court ruled in favor of Anthony Noto, who was accused of being a member of the Communist Party with an intent to overthrow the U.S. government under the Smith Act. The court held that mere membership or affiliation with such a group did not constitute sufficient evidence for conviction unless it could be proven beyond reasonable doubt that there was a clear and present danger posed by said individual or group towards national security. The prosecution failed to provide substantial evidence proving that Mr. Noto had actively engaged in activities aimed at overthrowing the government; therefore, his conviction was overturned on grounds of insufficient proof.

In the dissenting opinion for NOTO v. UNITED STATES, Justice Brennan disagreed with the majority's view that mere membership in an organization advocating violent overthrow of the government is sufficient to convict a person under Smith Act. He argued that this interpretation goes beyond what Congress intended and violates First Amendment rights. According to him, there must be clear evidence of active participation or personal advocacy by the defendant in order to justify conviction. Furthermore, he criticized the majority for failing to establish a clear standard on how much knowledge about an organization's illegal activities is necessary before membership can be considered criminal activity itself. In his view, such ambiguity could lead to arbitrary enforcement and potential abuse of power.