Since Monday night's debate, I've heard scores of Romney supporters express disappointment and surprise that Mitt Romney did not hammer away at President Obama on growing scandal regarding the attacks in Benghazi that killed Ambassador Stevens and three other Americans.
But it likely wasn't a Romney gaffe — Romney's near-silence on Benghazi was on purpose.

Now that the mainstream media is investigating and reporting on Benghazi and what Obama knew and when he knew it, Romney knew if he made it a centerpiece of the debate, his statements would be the news, complete with the parsing and "he said, he said" rather than reporting on the facts of the case. Lest yet another debate moderator feel the need to "fact-check" in a way that misleads voters, Romney's best bet was to let the story unfold without providing himself as a reason to divert from the subject at hand. He gave it room to breathe.
Reuters is reporting that President Obama knew immediately there was no protest and attack over a video, and that it was a terrorist attack. This, before he left to raise money in Las Vegas. There is no mention of Mitt Romney's syntax in addressing the issue.