The Anti-Federalists feared that if the Constitution was ratified (became law) that it would give far too much power to the federal government over the states--leading to tyranny and the trampling of individual rights.
Answer:
the Roman empire fell for many reasons, but the 5 main ones were invasions by Barbarian tribes, Economic troubles, and overreliance on slave labor, Overexpansion and Military Spending, and Government corruption and political instability.
(Gave information from teen link)
The Declaration of Independence.