During last year's presidential campaign, federal loan guarantees for alternative-energy companies became a GOP punch line. Mitt Romney referred to some of the recipients as "losers." Paul Ryan said they addressed "make-believe markets." Marco Rubio claimed that the Department of Energy was "wasting more taxpayer money," based largely on the well-publicized failure of solar-panel maker Solyndra. But a funny thing happened on the way to the burial: The loan program began to work. Thousands of jobs have been created. Domestic energy production is more diversified. Most important, the U.S. taxpayer is being set up for a possible profit.