I suspect the question was a set up, and Romney knew it was a set up. Obama was probably primed to nail him hard with some practiced counterattack, but by not attacking, it takes the wind out of the blowhard.
Common sense, if you are boxing someone you know has a devastating right thrust counter-punch, you keep pivoting to their left, hitting them with jabs, and not walking into their optimal range. If they still try to nail you with it, outside of its range, it will mean a lot of wasted energy in an ineffective attack.
The problem with Libya is Obama and his Obots are providing multiple narratives. All he really needed to do is get out of the way.
“I suspect the question was a set up, and Romney knew it was a set up”
I was thinking the same thing. Every voter with more than a single digit IQ is pretty much aware of Obama’s feckless handling the Libya crisis. Schiffer was probably waiting with another out-of-context word game provided by David Axeldork (i.e. Candy Crowley’s “terrorism” quote) as soon as Romney made any specific reference to to this issue.