True, but in the prev. cases the credible information did come out. Now, I could be wrong, but I don’t think even Obama would move against Assad on information that pointed to the rebels. Enough time has passed for indications one way or another to be evident, if indeed we do have (or have put) people on the ground in the area.
On the other hand, I’m also open to the idea we colluded with the rebels to implicate Assad, so in that case we have Obama placing the cheese in the trap he built for himself, while Putin observes, smiling.
Looking at Egypt and Benghazi, I’d say the latter seems more likely.