I've been wondering this for a while now (please make sure your tin foil is in the upright and correct position). What if what we know outside the MSM about Benghazi is true; weapons running to AQ and the MB. Rumors of stolen/swapped manpads. Lets just say fast and furious on a nefarious international level. How far outside the realm of possibility would it be that another nation hit US to stop that activity? Might explain why no one wants to investigate as "we" (this administration, not all Americans) are the enemy now.
Just food for thought, I have nothing to back up that notion other than wondering how long other nations are going to put up with our crap.
Thinking further on it, it might explain why cross border authority (Read Travis McGee’s awesome write up) was not given after all, some other big dogs were in there and the risk of a full blown international incident would bring light to what we are doing supplying muzzies..