The Han, Roman and Gupta empires all fell do to invasion. A strong, loyal army is necessary to protect the empire from invasion. All of these empires were first weakened by a succession weak governments. The trust and faith in the government was eroded over time. Internal strife by the people because of declining abilities of the government to govern weaken the state. The government should try to prevent internal rebellions by maintaining good governance over the people.
The articles of confederation was drafted after the revolutionary war. But later on this would also create issues since the power was given to states and not to the Federal government.
