Who fights your wars?
What kind of people do you get to fight futile wars? Do you send smart people, or people who are ready to die in the service of any objective no matter how pointless? Do you actively recruit and send forth the people who would make life better or the people at home, or the ones we can all do without?
Forget about Iraq or Bush or anything like that. Boil this down to the basic concept. You need a war that will be beneficial for certain reasons, but it not an essential war in that the safety of your citizens is not threatened, and nobody is in any danger of being invaded. Do you go tossing your best at the “enemy” or do you take the opportunity to get rid of some dead weight?
War could be seen as an equivalent of Keynesian hole-digging. You dispatch soldiers to another country, or to your borders, where they wait and, occasionally, die. They send home money as they do all of this, and are kept occupied, maybe even pick up a few skills and most of everybody is happy. But you don’t do this with the people who might actually be getting something done in other areas. You put only your most expendable in danger.
