It's all about special interests.
Sens. Tom Harkin, D-Iowa, and John McCain, R-Ariz. want the dollar bill eliminated and replaced by a coin.
Harkin and McCain both represent states that are home to businesses that profit from the production of dollar coins. In Harkin's case, it's PMX Industries Inc., of Cedar Rapids. The company provides metal sheets the U.S. Mint uses to make coins. McCain's state, Arizona, has the nation's most productive copper mines, and dollar coins are made mostly of copper.
Harkin has a bill before Congress that would require Federal Reserve banks to stop putting $1 bills into circulation in as little as four years.
There's also the fact that people just don't like carrying around coins, which means they put them in jars and don't spend them, which gives an edge to the Treasury when it first spends them into circulation.
There's one bit of upside to this nutty plan, eventually price inflation will get so bad that the metal value in such coins will be worth more than one dollar and they will disappear from circulation, the way silver dimes and quarters have. It won't happen any time soon, there won't be near enough metal value in the coins at first, but it will eventually.