_The contract obligation ... was not a duty to pay gold or silver, or the kind of money recognized by law at the time when the contract was made, nor was it a duty to pay money of equal intrinsic value in the market.... But the obligation of a contract to pay money is to pay that which the law shall recognize as money when the payment is to be made.--Legal Tender Cases, 12 Wallace 548._ This is saying that the obligation of a contract to pay money is not an obligation to pay what both the law and the parties recognize as money, _at the time when the contract is made_, but only such substitute as congress shall afterwards prescribe, "_when the payment is to be made_." This opinion was given by a majority of the court in the year 1870. In another opinion the court says: Under the power to coin money, and to regulate its value, congress may issue coins of same denomination [that is, bearing the same name] as those already current by law, but of less intrinsic value than those, by reason of containing a less weight of the precious metals, _and thereby enable debtors to discharge their debts by the payment of coins of the less real value_. A contract to pay a certain sum of money, without any stipulation as to the kind of money in which it shall be made, may always be satisfied by payment of that sum [that is, that _nominal_ amount] in any currency _which is lawful money at the place and time at which payment is to be made_.--_Juilliard vs. Greenman_, 110 _U. S. Reports_, 449. This opinion was given by the entire court--save one, Field--at the October term of 1883. Both these opinions are distinct declarations of the power of congress to alter men's contracts, _after they are made_, by simply retaining the name, while altering the thing, that is agreed to be paid. In both these cases, the court means distinctly to say that, _after the parties to a contract have agreed upon the number of dollars to be paid_, congress has power to reduce the value of the dollar, and authorize all debtors to pay the less valuable dollar, instead of the one agreed on. In other words, the court means to say that, after a contract has been made for the payment of a certain number of dollars, _congress has power to alter the meaning of the word dollar_, and thus authorize the debtor to pay in something different from, and less valuable than, the thing he agreed to pay. Well, if congress has power to alter men's contracts, _after they are made_, by altering the meaning of the word dollar, and thus reducing the value of the debt, it has a precisely equal power to _increase_ the value of the dollar, and thus compel the debtor to pay _more_ than he agreed to pay.