An interesting opinion piece-
http://pajamasmedia.com/michaelledeen/2008/08/14/war-and-democracy/
"The belief in the inevitability of peace and democracy rested on one of the great conceits of the European Enlightenment, namely the belief in the perfectibility of man. In this view, man’s basic goodness (as found in “the state of nature”) had been corrupted by a selfish society (a notion that finds much favor among today’s more extreme Greens), but that once the heavy weight of misguided was lifted, man’s intrinsic goodness would reemerge. In our modern rendition of that Enlightenment folly, an appeal to reason is sufficient to change the world. Back in the Clinton years, it was widely believed that all future conflict would be solely economic; the age of military warfare had passed, henceforth products, markets, and human ingenuity would determine who is rightly top dog and who needs to get with the program. And so the defense budget was slashed, military men and women were treated with contempt by the president and his wife, and we turned inward. After all, if historical inevitability ruled, why bother with national security? Tyranny was considered a passing phenomenon, headed for the ash heap, and certainly no threat to us."...
..."The American Founders knew it: recognizing man’s innate capacity for evil, they designed a system of checks and balances to thwart the accumulation of power by any group, lest the entire enterprise fall into wicked hands. They knew the battle for liberty would never end, Benjamin Franklin famously warned we would have to fight to keep our republic."