In March 2010, the accounting firm PricewaterhouseCoopers issued a standard but stern warning about Solyndra, a California solar panel manufacturer: The company wasn't making money and never had, which raised "substantial doubt about its ability to continue as a going concern." Yet when President Obama visited Solyndra's plant in Fremont two months later, he gave a rousing pep talk and declared that "the future is here."

Alas, it wasn't.

Solyndra continued to struggle, canceled a planned public stock offering and filed for bankruptcy this month — leaving the U.S. government as its biggest creditor and raising new questions about whether Uncle Sam should be playing venture capitalist.

Despite initial misgivings about the company's viability, an Energy Department program aimed at boosting "clean energy" projects had guaranteed a $535 million loan to Solyndra, which produced an innovative but expensive solar panel. Taxpayers are now on the hook for some or most of that money, depending on whether someone buys the assets.

Whether Solyndra is just an expensive embarrassment, or a full-fledged scandal, remains to be seen. Shortly after the bankruptcy filing, the FBI raided Solyndra's headquarters and the homes of its executives in connection with the loan. And today, a House oversight panel holds a hearing to probe how the company — whose board and investors included some major campaign donors to Democrats and Obama — got the money, and whether the administration properly vetted the application.