Have you hear of the Dunning-Kruger effect? Well, neither had I until today, but now that I have, I must say I think it explains quite a lot. I came across a discussion of the effect in a blog that I follow called Skeptical Science. It's a blog that explains sometimes very complicated scientific concepts in relatively easy-to-understand layman's (or laywoman's) terms.
Dunning and Kruger are two Nobel Prize winning scientists who wrote a scientific paper for the Journal of Personality and Social Psychology called "Unskilled and unaware of it: How difficulties in recognizing one's own incompetence lead to inflated self-assessments." I love that title and it pretty much says it all.
The "effect," as I understand it, is that the more unskilled or unaware an individual is, the more likely his/her assessment of his/her own abilities is likely to be inflated and not consistent with reality. Conversely, as one's skills and knowledge level increases, one tends to be more realistic or even modest in evaluating oneself. If you look around, I think you can find plenty of examples to illustrate this effect in public life today, but I can best describe it using myself.
I can remember (barely) that, years ago, I used to believe that I was pretty smart. Fresh out of college with my shiny new degree, I was ready to take on and conquer the world. As life experiences accumulated, I began to realize that not only had I not been nearly as smart as I originally thought, but I had also been hopelessly naive. Through the years, my assessment of my abilities has been adjusted downward time and time again until I think I may be finally nearing a realistic view of what I can actually do and accomplish in life. It is a humbling process, but one that anyone with an ounce of self-awareness must go through in their life.
One could only wish that some of our more self-important and self-aggrandizing leaders would go through that process - the sooner the better. But perhaps that is one of the hallmarks of such people; i.e., they go through life with the firm idea implanted that they are smarter than everybody else and that they can change the world. Sometimes, they even manage to do it, but not necessarily for the better.