DeJonge v. Oregon, 299 U.S. 353 (1937)
Communists may peaceably assemble.
An Oregon law prohibited Communists and others whose ideology advocated the overthrow of the U.S. government from meeting to express their ideas. DeJonge and others were arrested at a local meeting of communists. DeJonge was tried and convicted under Oregon law. He challenged his conviction, citing First Amendment concerns, and the Supreme Court agreed to hear his case. The Supreme Court ruled that, although taking steps to overthrow the U.S. government would certainly be a crime, the mere peaceable assembly of communists to discuss their ideology was not a crime. Dodging's conviction was reversed.

Thornhill v. Alabama, 310 U.S. 88 (1940)
Peaceful picketing is constitutionally protected.
Alabama enacted a law that prohibited workers from striking and picketing their place of employment. When workers called a strike and picketed their place of work, Thornhill, the leader of their union, was arrested. Thornhill challenged his conviction, arguing that the right to picket is protected by the First Amendment. The Supreme Court agreed and held, with certain exceptions, that the first Amendment protects the right to picket, and, in certain contexts, of workers to strike. In particular, the Court noted that picketing was a means for bringing labor issues to the public's attention and, thus, was particularly protected by the First Amendment.