It is interesting to note, multiple US Intelligence agencies were very much aware Al Qaeda was planning an attack. If you read the 9/11 Commission Report, it demonstrates that due to laws, these intelligence agencies were not permitted to share suspicions and evidence among eachother. Citing laws/policies, almost all intel gathered had to be kept within its respective department. They all had individual pieces of the puzzle, but they could show one another what they had.
If I remember correctly, there was supposed to be a huge overhaul of the intelligence system to prevent that kind of compartmentalization. Not sure how or if it ever got implemented (correctly), but I do know the government was supposed to be trying to fix it.
Never got implemented. Not correctly at least. I know from my experience, the DOJ and military barely communicate. Military and CIA communicate on an "as-needed" basis but I dont know who is in charge of what exactly is "as-needed."
FBI, CIA, and Military rarely share intel to solve things. It seems like a dick measuring contest of who can.solve it first or who can hide what. Hence, information from Benghazi is so fubar. Honestly, communication within our own government is a fucking joke and pathetic. Even within individual agencies, its still a sad sight to watch.
Also, i swear he has had more vetoed but I believe it was the SCOTUS that has vetoed him. Not congress.