Now, as nearly as I can make out, those fellows in the CIA don't just report on wars and the like, they go out and make their own, and there's nobody to keep track of what they're up to. They spend billions of dollars on stirring up trouble so they'll have something to report on. They've become ... it's become a government all of its own and all secret. They don't have to account to anybody.
That's a very dangerous thing in a democratic society, and it's got to be put a stop to. The people have got a right to know what those birds are up to. And if I was back in the White House, people would know. You see, the way a free government works, there's got to be a housecleaning every now and again, and I don't care what branch of the government is involved. Somebody has to keep an eye on things.
And when you can't do any housecleaning because everything that goes on is a damn secret, why, then we're on our way to something the Founding Fathers didn't have in mind. Secrecy and a free, democratic government don't mix. And if what happened at the Bay of Pigs doesn't prove that, I don't know what does. You have got to keep an eye on the military at all times, and it doesn't matter whether it's the birds in the Pentagon or the birds in the CIA.
Harry S. Truman
Source - https://mises.org/blog/truman-was-right-about-cia
In fact, the entire "national security state" concept is the opposite of a democratic society. But we are so deep in its clutches that we'll never extricate ourselves.