In the case of Fiswick et al. v. United States (1946), the U.S Supreme Court ruled on whether a naturalized American citizen could be convicted for treason committed before his naturalization process was complete. The defendant, Carl Wilhelm Fiswick, had been charged with treason for actions taken during World War II while he was still in the process of becoming an American citizen but after he had declared his intent to do so. The court held that a person who has declared their intention to become a U.S citizen and is residing in America can indeed be tried and convicted for treason if they commit acts against the United States during this period of residency prior to full citizenship being granted. This decision clarified that one's loyalty to America begins when they declare their intent to become citizens, not just when formal citizenship is conferred.

In the dissenting opinion for Fiswick et al. v. United States, Justice Murphy argued that the majority's interpretation of "foreign government" in Section 6 of Title 50 U.S.C., which includes governments not recognized by the United States, was incorrect and overly broad. He contended that this interpretation could potentially criminalize innocent actions or associations with unrecognized foreign entities. Furthermore, he disagreed with the majority's view on conspiracy charges; he believed that a person should only be convicted if they were aware their actions would contribute to an illegal objective - simply being part of an organization isn't enough to establish guilt without knowledge or intent towards its unlawful goals.