Knox v. Lee held that the Legal Tender Act was constitutional. Hepburn was now overturned by a 5-4 vote. In Knox, the majority found that the Legal Tender Act was made “necessary” by the shortage of gold and silver during the Civil War.
Knox did far more than uphold the Legal Tender Act. The decision also adopted a construction of the Necessary and Proper Clause that was even broader than Justice Story’s analysis in Prigg v. Pennsylvania. The “non-enumerated powers” granted by this Clause, Justice Strong wrote, “reach beyond the mere execution of all powers definitely intrusted [sic] to Congress and mentioned in detail.” Indeed, Justice Strong stated it was “not indispensable” that an implied power “be found specified in the words of the Constitution, or clearly and directly traceable to some one of the specified powers.”