Here's another sign of the Obama camp's message shift in the direction of a full-throttle push on energy. With no public announcement, the Obama campaign quietly started airing this ad yesterday in a few select states -- it's very similar to this spot released last week hitting McCain for taking the "low road," but the new spot adds a new introduction hitting McCain on gas prices.A source sends along a copy...Our source notes that it's on the air in Pennsylvania, where Obama surrogates have been going after McCain's negative campaigning very aggressively in the local media. It's also running in a couple of other battleground states, though it's unclear right now which ones. Anyway, it's another sign that the energy wars are in full swing.Late Update: For a few minutes we had vid of the old ad posted. The new one is now above. Apologies.