Charlemagne was a greater leader who unified his kingdom by fighting off invaders. He also unified the Kingdom using Christianity. He was also an astute administrator who ran an orderly government and bureaucracy. As a result, he was able to maintain order throughout the empire
The Founding Fathers compromised on using a federal system for the new government because a federal system would create a system of power sharing between the national and state governments. There was great debate about state v. federal power in the writing of the constitution and the choice of a federal system was a compromise which sought to implement and protect the concerns of creating a tyrannical federal government but also one that could provide for the people with a strong national government.
The cholera epidemic. The others were factors, but not as serious.
The only two places where Ronald Reagan did not win the electoral college were Minnesota and Washington DC. Besides that, Reagan won every single state in the US. This resulted in one of the biggest political landslides in US history, as Reagan received 525 electoral votes to Walter Mondale's 13.
