Rousseau believed in the concept of direct democracy, in which people directly decide on the policies and laws of a government. There is no actual direct democracy in existence by any government, presumably because in order for a state to exist it relies on the oppression of the people ruled under it. A direct democracy would give too much power to the people, many of whom may realize that laws and governments are inherently unjust and choose to do away completely with states. In fact, Rousseau recognized that people have never been as free as they were before the rise of civilization. With the rise of civilization came the rise of states, and because of governments, as Rousseau noted, "man is born free and everywhere he is in chains."
Rousseau's idea of the Social Contract is often quoted in relation to, particularly, the creation of the US constitution and the French constitution. The idea of the Social Contract is that governments exist by the consent of the people, or, the consent of "the governed". However, this is an incredibly simplified and blatantly false understanding of the creation of states. The United States, for example, was created through genocide and slavery, which is the exact opposite of consent. And when the state was created, with many of Rousseau ideas found throughout the American Declaration of Independence, black people were still enslaved in mass, indigenous people were still being horrifically oppressed, and women denied autonomy over their own lives.