Negligence - No.
Not negligence, because it was all part of her plan.
For the election, Obama needed to show that he could be tough on Islam.
He planned to have the Ambassador kidnapped and then he would get tough on the terrorists and they would give the Ambassador back, all as per Obama/Hillary plan. Obama a hero, election in the bag.
He stripped away all the security to make it easy. Problem was that some Navy Seals showed up and started kicking some Muslim butt. Terrorists figured they were set up and the real plan was to wipe them out. They thought that Obama was trying to be the hero by defending the Ambassador.
Things spin out of control, Ambassador is abused and killed Muslin style. Obama and Hillary have to go into spin and lie mode.
It seems to me that the facts of what happened seem to fit well into this scenario.
But will enough notice or care?