Its history! Greek empire, roman empire, british empire, mongol and on and on.They all extended themselves, and it happened.Our peace loving country has fought france, england, japan , germany, korea, china, russia,and that also go's on.When you have troops in at least 20 different countrys, the financial drag will eventually bring you down.But it wasn't the military the world looked up with us, it was the idea of freedom, of unlimited personal destiny, these things are eroding also.