The end of the Roman Republic was attributed to the instability of the Roman economy and conflicts within the military and the ruling families. The Republic should have moved towards absolute democracy instead of relying on the royal families to govern the country.
The correct answer is manifest destiny.
Manifest destiny is the belief that it was America's god given right to expand from "sea to shining sea." In other words, it was America's destiny to expand their control across the entire North American continent from the Atlantic to the Pacific Ocean. This belief resulted in the US buying land from other countries, fighting in wars, and taking land from Native Americans in order to achieve this goal. This was present throughout American society during the early to middle of the 19th century.
Europe maintained unity after the Roman Empire. 1 through The power of the Papacy and the Christian faith, and 2 Through Feudalism because even though it caused fractures in regions it offered a clear power structure that allowed Strong nations to bring their weaker neighbors under their direct control.
