Because of the Industrial revolution europeans were envy to expand with their new found wealth. Because of the money gained from the industrial revolution they could try to take control of other foreign territories in means of expanding for their own personal gain
1. It never lead to a single large conflict. Rather many smaller ones.
2. During the Cold War, the USA and USSR both funded army’s of smaller countries to fight for them. For instance the Korean and Veitnam Wars.
3. The Cold War came to a close when the Soviet Union dissolved in 1991.
The Continental Congress commissioned George Washington as Commander in Chief of the Continental Army on June 19, 1775. Washington was selected over other candidates such as John Hancock based on his previous military experience and the hope that a leader from Virginia could help unite the colonies.
The idea of the social contract theory comes from Jean Jacques Rousseau's book the Social Contract but one of the most prominent philosophers that discussed the idea was Thomas Hobbes who describes social contract as a contract between the individuals and the government, whose authority comes from the people. The people would cede some of their rights to the government for protection and the sovereign is bound by the wishes of the people as it is they that govern his decisions.
So the question of John Stuart Mill relate to the theory of the social contract very much. The main issue is exactly how many rights would the people have to cede and what would be the right balance between the independence and the obedience to the social contract. That is a very thin and tricky line to navigate.