In Opper v. United States, the Supreme Court ruled that a defendant's admission of facts or elements of a crime can be used as evidence against them even if it does not amount to a full confession. The case involved Morris Opper, who was charged with defrauding the government by submitting false claims for reimbursement while working at the War Assets Administration. During his trial, statements he made admitting certain aspects of the fraudulent scheme were used as evidence against him despite not being an outright confession to committing fraud. He appealed on grounds that this violated his Fifth Amendment rights against self-incrimination and due process rights under Fourteenth Amendment but was denied by lower courts leading up to Supreme Court review. The court held in 5-4 decision that such admissions could indeed be used as long they are corroborated by independent evidence establishing their trustworthiness beyond reasonable doubt; thus affirming conviction and setting precedent for future cases involving partial confessions or admissions.

In the dissenting opinion for Opper v. United States, Justice Minton argued that the majority's decision was a departure from established precedent regarding corroboration of confessions in federal criminal cases. He contended that previous rulings required independent evidence not only to establish the corpus delicti but also to connect the defendant with it before a confession could be admitted into evidence. In this case, he believed there was no such corroborating evidence linking Opper to any wrongdoing apart from his own statements and therefore his conviction should have been reversed. Furthermore, Justice Minton expressed concern about potential abuses if uncorroborated confessions were allowed as sufficient proof of guilt without additional supporting evidence.