Rousseau begins The Social Contract with the notable phrase "Man is born free, but everywhere he is in chains." Because these chains are not found in the state of nature, they must be constructions of convention. Rousseau thus seeks the basis for a legitimate, political authority in which people must give up their natural liberty. He sets two conditions for a lawful polity and creates several clauses to ensure that they are carried out. First, there must be no relationships of particular dependence in the state, and second, by obeying the laws, an individual only obeys himself.
Rousseau's solution to the problem of legitimate authority is the "social contract," an agreement by which the people band together for their mutual preservation. This act of association creates a collective body called the "sovereign." The sovereign is the supreme authority in the state, and has its own life and will. The sovereign's interest, or the "general will," always promotes the common good. This is in contrast to the private will of each citizen, which strives only for personal benefit.
The law expresses the general will, and must only make regulations that affect the entire populace. The goal of legislation is to protect liberty and equality and to promote the common good. However, the people may not always know how to pursue the common good and may need the help of a legislator to guide them in lawmaking. The legislator prevents private interests from influencing legislation and aids the populace in weighing short-term benefits against long-term costs.
Although the sovereign exercises legislative authority, the state also needs executive power to implement the general will. There are three main types of government: democracy, aristocracy, and monarchy. The type is chosen based on several factors, including population and climate. Smaller governments have more force than larger ones, and the population becomes more unruly as it grows. Rousseau thus argues that in general, there should be an inverse relationship between the size of government and the size of the population. Thus, large states should have a monarchy, intermediate states should have an aristocracy, and small states should have a democracy.
Rousseau asserts that the establishment of government is not, as philosophers such as Hobbes and Grotius have argued, a contract. The sovereign employs the government as a representative of the people in charge of carrying out the general will. The sovereign thus can alter the form of government and replace its leaders as it chooses.
As the natural tendency of every government is to usurp sovereignty and to invalidate the social contract, the government's interests are always in conflict with those of the sovereign. The best means of restraining the executive is holding periodic assemblies. Although this may seem difficult, Rousseau cites Ancient Rome to show that this can be achieved even in large states. When the people convene, they must decide whether they approve of the current form of government and their leaders.
Periodic assemblies can prolong the life of a state, but eventually every state will fall because of the usurpations of government. However, all citizens must fulfill their civic duties while the state exists. They cannot employ representatives to articulate the general will because sovereignty cannot be transferred. They also cannot use money to avoid their responsibilities, because this corrupts the state and destroys civil liberty.
When voting, each person must assess whether a law is in accordance with the general will - not whether it supports his private interests. Thus, he has an obligation to follow even those laws to which he does not give his consent. In a healthy state, people share common sentiment and show unanimity in the assemblies. In a declining state, people place their private interests above the common good and try to manipulate the legislative process.
Although the sovereign must allow for the religious freedoms of its members, it can impose a set of values that are necessary to being a "good" citizen. This system of beliefs, which Rousseau calls "civil religion," consists of belief in a God and the afterlife, universal justice, and respect for the sanctity of the social contract. The state has the power to banish from the state anyone who opposes the tenets of civil religion.