How does the concept of the social contract theory contribute to the foundation of political legitimacy?

The social contract theory is a philosophical model that typically posits that individuals have consented, either explicitly or tacitly, to surrender some of their freedoms and submit to the authority of the ruler or magistrate (or to the decision of a majority), in exchange for the protection of their remaining rights. The theory has served as a foundational element for the development of modern political systems, influencing the establishment of political legitimacy.

Notable thinkers such as Thomas Hobbes, John Locke, and Jean-Jacques Rousseau have provided various iterations of this theory. Each presents a different version of the contract and what it entails for the formation of society and government.

For example, John Locke's version of the social contract is explicitly concerned with the protection of natural rights, including life, liberty, and property, and this has heavily influenced the development of liberal democratic thought.

Reference: Stanford Encyclopedia of Philosophy, Social Contract Theory.