pretty much falling on her sword over Libya, which, actually, probably makes sense ... to the extent that it actually represents a catastrophic failure as opposed a durable risk at that moment exposed.
Again, FTR
Carter: Tehran (52 hostages + a delta team)
Reagan: Lebanon (what was it 240 Marines?)
Bush I: sure, go ahead and invade Kuwait ... er, well, not like that.
Clinton: USS Cole. Somalia
BushII: being born, WMDs, and , uh oh yea ... 911
Obama: Benghazi
Seriously, Benghazi versus any of the above pales in the "failure scale".