In Margolin v. United States (1925), the U.S Supreme Court addressed an appeal by a defendant convicted of conspiracy to defraud the United States through false claims. The appellant, Margolin, argued that there was insufficient evidence to support his conviction and that he should have been granted a new trial due to newly discovered evidence. However, the court rejected these arguments and affirmed his conviction. The case centered on whether certain documents were admissible as evidence in proving intent for fraud against the government. These documents included letters between co-conspirators which contained statements about their fraudulent scheme but did not directly implicate Margolin himself. The Supreme Court held that such indirect proof could be used as circumstantial evidence of guilt if it demonstrated knowledge or participation in the conspiracy. Furthermore, they ruled that granting a new trial based on newly discovered evidence was at discretion of lower courts unless clear abuse is shown - something which had not occurred here according to them. This decision reinforced legal principles regarding evidentiary standards in criminal trials and judicial discretion over requests for retrials.

The dissenting opinion in Margolin v. United States argued that the majority's decision to uphold the conviction of a man for selling morphine unlawfully was incorrect because it relied on an overly broad interpretation of what constituted "professional practice" under federal law regulating narcotics. The dissent contended that this expansive reading could potentially criminalize legitimate medical practices, as it did not sufficiently distinguish between lawful and unlawful dispensation of drugs by physicians. It also criticized the majority for failing to consider whether there was sufficient evidence to prove beyond reasonable doubt that the defendant had acted outside his professional capacity when he sold morphine without a prescription, which is required by law for conviction under this statute.