It’s a blogosphere truism that insanity consists of doing the same thing over and over, expecting a different result. There is wisdom there, but the aphorism ultimately fails on the matter of terminology rather than substance.
The defining characteristic of a fool is inappropriate and dogged persistence. That’s why it’s impossible to make things foolproof — a fool is somebody who will pick at the scab until he dies of septicæmia, wiggle the loose bit until it breaks, or keep pushing ’til the thing falls over. A child who sticks a hairpin in a light socket is an ignorant person experimenting with the World; an adult who does so is a fool.
Fools can be, and often are, highly intelligent in the sense of problem-solving ability. This just makes them more dangerous, because it means they can do destructive things more capably and with better attention to detail. A stupid fool presses buttons until disaster comes. A bright fool notes the response of the buttons as he presses them, reasons out which button is likely to produce the brightest flash and/or the most smoke, and zeroes in on it like a cat rushing for the food bowl.
Insanity comes closer to being an appropriate characterization, but still doesn’t fit. People who are insane don’t respond properly to stimuli — paranoids may have real enemies they should guard against, but the point of paranoia as insanity is that paranoids don’t take rationally appropriate measures against either their real enemies or their fancied ones. Fools select their methods and goals on an ultimately rational basis — the problem isn’t the reasoning power, it’s the things they reason about.
The people currently running things are neither stupid nor insane. They’re fools; the distinction is important and should be more widely recognized. The fact that fools keep getting into positions of power just further militates against calling them “insane”. One of the important factors in diagnosing insanity is whether or not the individual being judged reacts according to the norm for the population, and the rest of us keep selecting fools for power positions, eh?