The Supreme Court case Girouard v. United States in 1945 revolved around the issue of naturalization and loyalty to the United States during wartime. The petitioner, a Canadian-born man who had been living in the U.S., sought naturalization but refused to take an oath promising to bear arms on behalf of his adopted country due to religious beliefs as a Seventh-day Adventist. His application was denied by lower courts based on this refusal, citing that willingness to defend one's country is part of good citizenship and allegiance. However, upon reaching the Supreme Court, it was ruled that Congress did not intend for willingness or ability to bear arms be made a test for citizenship when drafting immigration laws. It noted that many native-born citizens may also be unable or unwilling due to physical disability or religious conviction yet they are not stripped off their citizenship rights because of this inability. Therefore, it held that while bearing arms is indeed an obligation which comes with American nationality under certain circumstances (like war), it cannot be used as a determinant factor for granting citizenship through naturalization process.

In the dissenting opinion for Girouard v. United States, Justice Frankfurter argued that the majority's decision to allow naturalized citizens who had renounced their allegiance to foreign powers during their naturalization process but later acted in a manner inconsistent with this pledge, was incorrect. He believed it undermined the importance of loyalty and commitment expected from those seeking American citizenship. The justice contended that when an individual swears allegiance to America during naturalization, they should be held accountable for any subsequent actions betraying this oath. Therefore, he disagreed with absolving such individuals of perjury or fraud charges related to their initial pledge of loyalty if they subsequently engaged in disloyal activities against the U.S., as it would set a dangerous precedent undermining national security and integrity.