Which Enlightenment thinker advocated for the separation of government powers?

Montesquieu is the Enlightenment thinker who advocated for the separation of government powers. He introduced this concept in his influential work "The Spirit of the Laws," where he argued that political power should not be concentrated in a single entity. Montesquieu proposed that dividing government into branches—executive, legislative, and judicial—would prevent any one branch from gaining too much power and thus provide a system of checks and balances. This idea became foundational for modern democratic governance, influencing the structure of many political systems, including the United States Constitution.

The other thinkers mentioned had significant contributions to political theory but did not focus specifically on the separation of powers. For example, Voltaire was known for his advocacy of civil liberties and freedom of speech, Rousseau emphasized social contract theory and general will, while Locke concentrated on natural rights and the role of government in protecting those rights. Each of these ideas is crucial to understanding Enlightenment thought, but Montesquieu's unique emphasis on the separation of governmental powers is what sets him apart in this context.