 The power to emit paper money (e.g.bank notes) has been justified by invoking the Necessary and Proper Clause in combination with the other enumerated powers which include the power to borrow money.The power to "issue bills of credit" is explicitly mentioned in the Constitution as a prohibition on the States, and could therefore be interpreted as a power so momentous that it would have to be conferred explicitly on the federal government rather than inferred from the Necessary and Proper Clause, although it is not entirely clear whether or not the framers intended such an interpretation, nor did the Supreme Court adopt such an interpretation in the Legal Tender Cases or subsequently.