Extreme nationalism, devotion to a single ruler, use of force and terror and censorship of information is called socialism, liberalism, fascism or ethnocentrism?

The best answer here is : Fascism.

Especially devotion to a single ruler is not a characteristics found in the other systems, as they're more focused on "the people" rather than on a strong ruler.

Socialism is an economical system based on a controlled market, liberalism calls for little control of the state and ethnocentrism is the focus on one's own ethnicity.

France played a key role in the american revolutionary war (american war of independence; 1775–1783). motivated by the ideals of the new nation which were inspired by the french enlightenment, as well as its long-term rivalry with britain and so as to avenge their territorial losses during the french and indian war, france secretly began sending supplies to the americans in 1775.