Perhaps Clifford's most prominent declaration against exercise of federal authority came in the Legal Tender cases. The cases dealt with Legal Tender Act of 1862, passed to permit the issuance of paper money to pay war debts and establishing that paper currency would be valid as legal tender. In "Hepburn v. Griswold" (1870), a debtor whose note was made prior to the Act's passage challenged its application to her debt. Clifford joined the majority in a 5–3 decision holding that the Legal Tender Act could not constitutionally apply to preexisting debts.