There is a lot of loose talk out there about the legal status of the Trillion Dollar Coin idea. Let’s go to the statute books.
31 USC § 5111
(a) The Secretary of the Treasury—
(1) shall mint and issue coins described in section 5112 of this title in amounts the Secretary decides are necessary to meet the needs of the United States;
(2) may prepare national medal dies and strike national and other medals if it does not interfere with regular minting operations but may not prepare private medal dies;
(3) may prepare and distribute numismatic items;
31 USC § 5112
(a) The Secretary of the Treasury may mint and issue only the following coins:
(1) a dollar coin that is 1.043 inches in diameter.
(2) a half dollar coin that is 1.205 inches in diameter and weighs 11.34 grams.
(3) a quarter dollar coin that is 0.955 inch in diameter and weighs 5.67 grams.
(4) a dime coin that is 0.705 inch in diameter and weighs 2.268 grams.
(5) a 5-cent coin that is 0.835 inch in diameter and weighs 5 grams.
(6) except as provided under subsection (c) of this section, a one-cent coin that is 0.75 inch in diameter and weighs 3.11 grams.
(7) A fifty dollar gold coin that is 32.7 millimeters in diameter, weighs 33.931 grams, and contains one troy ounce of fine gold.
(8) A twenty-five dollar gold coin that is 27.0 millimeters in diameter, weighs 16.966 grams, and contains one-half troy ounce of fine gold.
(9) A ten dollar gold coin that is 22.0 millimeters in diameter, weighs 8.483 grams, and contains one-fourth troy ounce of fine gold.
(10) A five dollar gold coin that is 16.5 millimeters in diameter, weighs 3.393 grams, and contains one-tenth troy ounce of fine gold.
(11) A $50 gold coin that is of an appropriate size and thickness, as determined by the Secretary, weighs 1 ounce, and contains 99.99 percent pure gold.
(12) A $25 coin of an appropriate size and thickness, as determined by the Secretary, that weighs 1 troy ounce and contains .9995 fine palladium.
(k) The Secretary may mint and issue platinum bullion coins and proof platinum coins in accordance with such specifications, designs, varieties, quantities, denominations, and inscriptions as the Secretary, in the Secretary’s discretion, may prescribe from time to time.
31 USCS § 5103
United States coins and currency (including Federal reserve notes and circulating notes of Federal reserve banks and national banks) are legal tender for all debts, public charges, taxes, and dues. Foreign gold or silver coins are not legal tender for debts.
Legislative History, Such As It Is, and Plain Language
Section (k) Was Added In By P.L. 104 – 208, the 1997 Omnibus Consolidated Appropriations Act. The provision isn’t discussed in the House Report or the Senate Report as best I can tell. The statute adds several provisions besides section (k) related to commemorative coins, which generally are regarded as numismatic or collectible coins as opposed to circulating coins. The point of those sections is to enable the Treasury to make a significant seigniorage profit on these coins, and to raise money to assist in worthy causes. There are numerical limits on certain of the coins, as in section (m), presumably to protect their numismatic value, although the Secretary of the Treasury is authorized to make more if there is sufficient demand. There is no similar limitation on issuance of platinum coins. In any case, all coins are legal tender, whether they are numismatic or intended for circulation.
In a similar way, the Treasury is authorized to print U.S. currency notes itself, but the amount is limited to $300 million. 31 USCS § 5115.
Section 5111 authorizes the Secretary of the Treasury to mint and issue coins as described in § 5112 in such amounts as the Secretary decides are necessary to meet the needs of the United States. This is very broad language, and does not appear to establish any limitation on the factors that might help the Secretary determine the needs of the United States.
Of course, our conservative Supreme Court Justices aren’t interested in legislative history (except when it suits them). They rely on the plain language of the law. It would be a real hoot to watch Justice Scalia explain why the plain language is not plain enough for him.
The Debt Ceiling