Hill: Sen. Lindsey Graham warns that President Barack Obama will kill the last hopes for comprehensive energy and climate change legislation if he cracks down on offshore oil drilling. In a sit-down interview with The Hill, the Republican senator from South Carolina said he is at a “crossroads” in deciding how to proceed on energy and climate change. He doesn’t think the signs look good given the fallout from the oil spill in the Gulf of Mexico. “Why would a person who really …