Bernie Sanders published his version of the Green New Deal last week, and it’s written with all the realism voters have come to expect. Start with its price: “an historic $16.3 trillion.” That’s 10 times Joe Biden’s climate plan, which is wild already. For the record, America’s annual economy is about $21 trillion.

Mr. Sanders says climate change “shares similarities with the crisis faced by President Franklin Delano Roosevelt in the 1940s,” when the U.S. “within three short years restructured the entire economy.” Oh, the...