In the case of Schackman et al. v. California in 1966, the U.S Supreme Court dealt with issues related to freedom of speech and assembly under the First Amendment. The appellants were members of a political group who had been convicted for violating a California statute that prohibited picketing near courthouses with an intent to interfere with or obstruct justice system operations. They argued that their activities were peaceful and intended only to express their views on racial discrimination within the judicial system, thus protected by First Amendment rights. The Supreme Court held that while states have legitimate interests in protecting courts from influences outside open proceedings, they cannot unduly infrive upon free expression rights guaranteed by Constitution's First Amendment. It was determined that this particular statute was overly broad as it could potentially punish those engaged in constitutionally protected activity along with those whose conduct may be legitimately proscribed. Therefore, convictions based on such statutes would violate constitutional protections unless there is clear evidence demonstrating actual obstruction or imminent danger thereof towards administration of justice due to defendants' actions.

In the dissenting opinion for Schackman et al. v. California, Justice Douglas argued that the First Amendment should protect peaceful demonstrations and picketing on public streets and sidewalks, even if they are near a courthouse. He contended that such activities were part of the freedoms of speech and assembly guaranteed by the Constitution. He also pointed out that there was no evidence to suggest these protests interfered with court proceedings or posed any threat to public safety or order. Therefore, he disagreed with the majority's decision upholding California's law prohibiting picketing near courthouses as it infringed upon constitutional rights without sufficient justification.