“Fog of War” is Hillary’s excuse for failing in her job.
Carl Von Clausewitz is the author of that term. It is part of his discussion on Friction of War in Book One of his 8 books, On War.
“Fog of War” is a reference to the chaos of multiple battles in a total war setting that, in reality, never go as planned. It refers to the confusion that every battlefield commander faces, and one of many challenges competent leaders must overcome.
When Hillary’s ambassador was attacked, raped, and slaughtered, it was in a single attack that was predicted days in advance. The country may be in a pseudo-state of war, but not so much that the ambassador required any security.
In other words, if her claim of “Fog of War” is to be believed, then she must answer the question: “Why did you have an ambassador in a war zone without any security?”