Harisiades v. Shaughnessy, 342 U.S. 580 (1952), was a United States Supreme Court case which determined that the Alien Registration Act of 1940's authorization of deportation of legal resident for membership in Communist parties, even past, did not violate the First Amendment, the Fifth Amendment, nor the constitution's Ex Post Facto Clause.

The 1951 Supreme Court case Dennis v. United States upheld prosecutions under the Smith Act for mere advocacy, as opposed to direct action, to violently overthrow the government as constitutional.

For example, people applying for residency, visas, or citizenship will be asked and investigated about their affiliations and can be denied based on what would normally be protected under the freedom of association, speech, etc.

[9] The cases of Harisiades, Mascitti, and Coleman, all legal residents, were consolidated into one due to the similarities in facts.

The majority affirmed the lower court's ruling on the case, rejecting the plaintiff's request to prevent their deportations.

[1] His primary argument was that the Alien Registration Act punished past belief and ideology, not conduct, and therefore violated the deportee's freedom of speech.