This is a blog post at Foreign Policy Magazine about the long term cost of mass mobilization wars. The biggest cost of having a war is the pension cost. The article points to a study looking at the true cost of the Iraq mess. the blog post has this interesting quote and and comment.
Suppose a drummer boy, age 14, became a soldier in 1861 and was disabled in that war. Suppose also that he married, had children, his wife died, and he remarried late in late, at say age 60 in 1907. Suppose further that his second wife was 25 years old at marriage and that at age 30 she bore him a child who was mentally or physically incapable of supporting himself. That child would be 57 years old today [that is, in 1969] and still drawing benefits — more than a century after the war ended.
Sounds unlikely, right? Yet Clayton nonetheless found that 1,353 dependents of Civil War veterans were still getting government benefits as late as 1967.