The difference between the 5th century BC and late 4th century BC at Athens is debt – and not caused just by military expenditures or war; the claims on Athenian entitlements grew by the 350s, even as forced liturgies on the productive classes increased, even as the treasury emptied. At Rome by the mid-3rd century AD the state was essentially bribing its own citizens to behave by expanding the bread and circuses dole, while tax avoidance became an art form, while the Roman state tried everything from price controls to inflating the coinage to meet services and pay public debts.
Remember, Jimmy Carter was loved up until about 1978, as he bragged of human rights, slashed defense to use the money for more entitlements, promised to get troops out of Korea, sold out the Shah, intrigued with the exiled Khomeini, pooh-poohed communists in Central America, sold warplanes without bomb racks to our allies, lectured on the inordinate fear of communism and sermonized how no one would die on his watch. ...
And then somewhere around 1979 the world finally sized him up — and the result was a bleeding American goat crossing the Amazon as the piranha swarmed. Radical Islam was on the rise. The Soviet army invaded Afghanistan. Nicaragua blew up. Iran took hostages. And in reaction Carter devised brilliant strategies like boycotting the Olympics and arming jihadists in Pakistan — and more lecturing us from the rose garden. He wanted a flashy hostage rescue mission — after slashing defense in 1977-8: but the two don’t mix, as he learned.
The message I get from all of this is "Brace for impact."