United States v. Diaz Conde

Summary

This landmark 1922 Supreme Court case established important principles regarding the retroactive application of criminal laws. The defendants were prosecuted under the Usury Law for collecting 5% monthly interest on a loan made before the law was enacted. While the lower court convicted them for collecting usurious interest after the law took effect, the Supreme Court reversed, holding that applying the Usury Law retroactively would violate constitutional prohibitions against ex post facto laws and impairment of contracts. The Court emphasized that interest obligations become part of the contract's principal obligation, and subsequent laws cannot criminalize previously legal acts. This decision reinforced the prospective application of penal laws and constitutional protections against retroactive criminal legislation, establishing precedent for contract interpretation and the temporal scope of criminal statutes in Philippine jurisprudence.