In the 1947 case Phyle v. Duffy, Warden, the U.S Supreme Court ruled in favor of Phyle who was convicted for perjury by a California court and sentenced to imprisonment. The conviction was based on his false testimony regarding his citizenship status during an earlier trial where he had been accused of violating federal immigration laws. In this appeal, Phyle argued that since his false statement about being a citizen did not influence the outcome of the original trial (as it wasn't material to its decision), it should not constitute perjury under California law which required such falsehoods be "material" to qualify as perjury. The Supreme Court agreed with him stating that whether or not a lie is material cannot depend solely on state definitions but must also consider federal standards given that this involved violation of federal law originally. Therefore, they concluded that since his lie didn't affect any substantial rights in relation to the initial proceedings (it wasn’t materially influential), it could not form basis for a valid perjury charge.

In the dissenting opinion for Phyle v. Duffy, Warden, Justice Frankfurter disagreed with the majority's decision to grant habeas corpus relief to a state prisoner who had exhausted all his remedies in state court and was not allowed federal review of his constitutional claims. He argued that this interpretation undermined principles of federalism by allowing federal courts to intervene prematurely in ongoing state proceedings. According to him, it also violated the principle of comity between states and the federal government by disregarding California’s interest in enforcing its own criminal laws without undue interference from other jurisdictions. Furthermore, he contended that such an approach could lead to unnecessary friction between different levels of judiciary system as well as potential abuse or misuse of habeas corpus power by lower-level courts.