The American people might be surprised to learn that for the past 20 years a handful of lobbyists and lawmakers—mostly from states with mining and metal-processing interests—have been pushing a proposal to take away dollar bills, and force the public to use metal coins instead.

The most recent attempt is the Currency Optimization, Innovation and National Savings (Coins) Act, sponsored by Sen. Tom Harkin (D., Iowa). This proposed law would prohibit the issuance of dollar bills after five years and replace them with dollar coins....