So name another empire that had a rapid military expansion just before it died. Militaries cost money, something dying empires lack. All those empires endured a long decline usually followed by a coup de grace to finish them off. You're just making up a bad narrative for the US and then claiming some historical precedence when you're wrong. The Roman empire, the Aztec, the Mali, the UK and most of Europe... all slow declines, some punctuated by an invading army.