Political fury over a failed $535 million loan guarantee to an Obama administration-backed solar company is threatening to poison the well for future green investments. The Obama administration is doubling down on its support for renewable energy, stressing that it will move forward on more loans like the one to Solyndra, the California-based company that announced its bankruptcy late last month. In fact, as many as 14 new loan guarantees from the Energy Department — nine of which are for solar projects — could be finalized by the end of the month. But congressional Republicans have signaled they’re prepared...