Jean-Jacques Rousseau was known to be an Enlightenment thinker and for writing the social contract theory. The theory took up the conditions for legitimate government, in line with his belief of popular sovereignty form of government. He also included in his theory that the government should be ruled by people because during his time, it was very difficult to have this kind of government on an individual basis. The government which is ruled by the people is the government that the United Stated now practiced, and other parts of the world. This type of government is governed by the means of voting system, which is also about democracy.