Lamont v. Postmaster General (1965)

The postal detention scheme violated the First Amendment because it imposed an affirmative burden on recipients who wished to access foreign communist materials—requiring them to identify themselves to government officials before receiving lawfully transmissible content. By conditioning delivery on explicit request, the statute created a chilling effect on the exercise of First Amendment rights: citizens would face potential surveillance and identification simply for requesting disfavored political materials, even though the materials themselves were not banned. The deterrent was structural rather than substantive—the government was not prohibiting the speech, but making it costly to receive it, which the Court found incompatible with the First Amendment's protection of the right to be informed. The law thus fell because it prioritized postal convenience and ideological gatekeeping over citizens' constitutional right to access foreign political ideas.