Polls say that many New Hampshire voters are selecting Sen. Bernie Sanders today for the Democratic presidential nomination. Mr. Sanders calls himself a “democratic socialist.” But Granite Staters who haven’t yet voted and citizens in upcoming primary states should note the latest news from a socialist state where the regime also spoke of democracy and originally came to power via the ballot box.

Even socialism’s leading practitioner in the country now acknowledges that private investment is the only way to save a critical...