Private business did try to do it back in 1934 and the same companies that were the cause of it are still around: JP Morgan, DuPont, etc. All these companies are still around and why because money buys innocence. These same companies caused the Great Depression and are the cause of our current one.
The NSA did take out JFK because he went against the grain. I can expect the CIA / NSA to do something like that because they have their own agenda. As for the military, well, they might or might not but for whose benefit (the peoples or a few individuals). Since they drink and eat the same food we do, they might be influenced by chemicals that are in our food (fluoride, mercury, etc) which is used to make us docile and lower our IQ.