The English philosopher whose Two Treatises of Government argued that legitimate political authority derives from consent of the governed, that natural rights to life, liberty, and property are inalienable, and that revolution is justified when governments violate those rights — providing the philosophical foundation of liberal democracy and the American Revolution.
When Jefferson wrote 'life, liberty, and the pursuit of happiness' he was paraphrasing Locke's 'life, liberty, and estate.' The American founders read Locke as carefully as any text outside the Bible. His argument that government derives its authority from the consent of the governed — and that revolution is justified when government betrays that trust — is the founding document of liberal political philosophy and the most influential political text of the modern world.