I am sadden by how many young lives were lost and even today lessons still have not learned.
I recall a number of Vietnam era "lessons learned" that were taught in various PME courses during my 20 years in the military. In fact,
here's an outstanding graph that shows both the fatalities as well as the fatality rate for all wars since the year 1400.
What really intrigues me is the second chart, "World-wide battle deaths per 100,000 people," showing just how much war has died down over the last 20 years. Whether it will stay that way is anyone's guess.
The site notes: "A recent paper, by Nassim Nicholas Taleb and Pasquale Cirillo, argued that our current peaceful era was a
statistical myth: that dips in war deaths should be expected, as Roser's chart shows, and that there's no reason to believe this time should be different. Pinker and others argue, by contrast, that things really have changed: that the rise of democracy, capitalism, industrial civilization, and international institutions like the UN have radically transformed the way global politics operates."
I'm of the personal opinion that the increase in international trade makes it more imperative for countries to settle their differences peaceably. However, that's by no means an absolute, and we still have the ever-rising tide of Islam to deal with.
PME: Professional Military Education