Lamont v. Postmaster General of the United States

The government appealed the decision in the California case, and Lamont appealed the district court's decision in the New York case, to the U.S. Supreme Court, which decided the cases together. The Supreme Court found that the statute was an unconstitutional restriction on the right to free speech.

The Court first rejected the government's argument that, because the government has no duty to provide for a postal service, the law did not involve any official action restricting the free speech rights of citizens wishing to receive material designated as communist propaganda. Quoting from Justice Oliver Wendell Holmes's dissenting opinion in the 1921 case of United States ex rel. Milwaukee Social Democratic Publishing Co. v. Burleson, the Court stated that "[t]he United States may give up the post-office when it sees fit, but while it carries it on the use of mails is almost as much a part of free speech as the right to use our tongues." Thus, the Court concluded, Congress by passing a statute was attempting to abridge the free speech rights of citizens to receive this material.

The Court also rejected the government's argument that the statute did not infringe on the right to free speech. The government argued that people could still receive material designated as communist propaganda by sending back the reply card directing the post office to deliver the material. Thus, the government argued, the statute involved only inconvenience, and not an abridgment of the right to free speech. The Court rejected this argument, reasoning that the statute requires an affirmative act on the part of the addressee in order to receive the prohibited materials. The Court also reasoned that people would be deterred from sending back the reply card, for fear that the government or others would label them communists. In his concurring opinion, Justice Brennan expressed the Court's view thusly: "[I]nhibition as well as prohibition against the exercise of precious First Amendment rights is a power denied to government . . . [W]e cannot sustain an intrusion on First Amendment rights on the ground that the intrusion is only a minor one." Thus, the Court found that the statute was unconstitutional.