LitCharts assigns a color and icon to each theme in The Social Contract, which you can use to track the themes throughout the work.
Human Freedom and Society
Sovereignty, Citizenship, and Direct Democracy
Government and the Separation of Powers
National Longevity and Moral Virtue
Summary
Analysis
Even “the best constituted” states eventually fall, and lawgivers must recognize this in order to set up effective ones. The body politic ages and dies like the human body: the stronger it is, the longer it will last, but it can never last forever. Specifically, its lifespan depends on that of its legislative branch, which is like its heart: the legislative power constantly revalidates the original laws of a country, and in a healthy state these laws become stronger over time because of the sovereign legislature’s continuous recognition. If the original laws instead grow “weaker with age,” this is a sign that the government is dying.
Just because a state dies, this does not mean that it has failed, any more than the fact that a person inevitably dies means that their whole life was a failure. By comparing the legislature (or the sovereign) to the heart, Rousseau is not only emphasizing that this agency is the most important one in government, but also revealing how a nation’s civic culture is like a muscle that must be actively exercised. When the government fails, the legislature can intervene by firing and replacing it, but when the sovereign legislature fails, there is no higher power to take its place. Therefore, if a state is properly structured, the most important factor in its longevity is not its structure but rather its culture.