John Locke's social contract theory is a political philosophy that posits that individuals consent to form a government in order to protect their natural rights, which include life, liberty, and property. This theory greatly influenced the founding principles of modern democracies, emphasizing the importance of government accountability and the right of citizens to revolt against unjust rule. Locke's ideas were pivotal during the debates surrounding the ratification of the U.S. Constitution, as they provided a philosophical foundation for individual rights and limited government power.