Romanticism definitely had its start in Europe. Most notably in England, France, and Germany with England being the one to first coin the phrase in the 1840's.
Both the Democratic and Republican Parties would support the idea that the United States should defend itself both in times of war and when it feels as though it's being threatened, since both parties believe deeply in national security.
It happened because the consuls only cared about their own personal wealth and not for the people. The senate got richer and richer while the people got poorer and poorer. It ended with the rise of the Empire and the rule of an Emperor. The disadvantage was that all of the power was in the hand of a single person and often the Roman emperors were tyrannical.
