Arthur Schlesinger reflects on the importance of history:

We are the world's dominant military power, and I believe a consciousness of history is a moral necessity for a nation possessed of overweening power. History verifies John F. Kennedy's proposition, stated in the first year of his thousand days: "We must face the fact that the United States is neither omnipotent or omniscient -- that we are only 6 percent of the world's population; that we cannot impose our will upon the other 94 percent of mankind; that we cannot right every wrong or reverse each adversity; and therefore there cannot be an American solution to every world problem."

History is the best antidote to delusions of omnipotence and omniscience. Self-knowledge is the indispensable prelude to self-control, for the nation as well as for the individual, and history should forever remind us of the limits of our passing perspectives. It should strengthen us to resist the pressure to convert momentary impulses into moral absolutes. It should lead us to acknowledge our profound and chastening frailty as human beings -- to a recognition of the fact, so often and so sadly displayed, that the future outwits all our certitudes and that the possibilities of the future are more various than the human intellect is designed to conceive.

Sometimes, when I am particularly depressed, I ascribe our behavior to stupidity -- the stupidity of our leadership, the stupidity of our culture. Three decades ago, we suffered defeat in an unwinnable war against tribalism, the most fanatic of political emotions, fighting against a country about which we knew nothing and in which we had no vital interests. Vietnam was hopeless enough, but to repeat the same arrogant folly 30 years later in Iraq is unforgivable. The Swedish statesman Axel Oxenstierna famously said, "Behold, my son, with how little wisdom the world is governed."