National Security issue

If proven that attack on WTC was carried by military/government forces as widely speculated where the term of National Security stands?

I am not lawyer so I have to ask this question

Because of such a power of this term, in wrong hands it could be catastrophic not only to one nation but to the whole world
One despotic man or some military/government establishment can bring disaster. It does NOT have to be whole government because the wise ones within can be easily psychologically terrorized and to scared to stand against. Could that be in case with Collin Power and some others?

 
I personally believe that such a term leading to hide documents should be withdrawn from use, from dictionaries and forgotten. More, not after time of 100% proof who attacked WTC but now, at present
What if there would be no time under nuclear mushroom or when terrorists attack UN buildings. The buildings float on dangerous waters currently

Such a term opens doors to catastrophe
There are no sufficient measures to prevent eventual catastrophic events at present
Is it really National Security if for example army carries attack on own citizens killing hundreds or thousands but hiding documents to cover such an act in the name of National Security?

 
Of course if caught those responsible will face consequences but is good enough? Is there any preventive mechanism to avid tragedies? Everyone would agree that prevention is much more important that chasing

Who is to decide that things are to be hidden for National Security reason?
How the Constitution and Law see it?
Is there any precise formula?

 
The best preventive measure it can be, is total disarmament all countries. It can and should be  done as soon as possible

I will write about how it can be done and how it will drastically improve security of individual countries and the whole world, soon...

J.L.