Who proposed the concept of the separation of powers in government?

The concept of the separation of powers in government was proposed by Montesquieu, a French philosopher and political theorist, in his work "The Spirit of the Laws". Montesquieu argued that to prevent any one individual or group from gaining too much power, governmental authority should be divided into distinct branches—executive, legislative, and judicial. This separation was meant to create a system of checks and balances, whereby each branch could limit the powers of the others, thus promoting liberty and preventing tyranny. Montesquieu's theories significantly influenced the framers of the U.S. Constitution and numerous other democratic systems around the world, making his ideas foundational in the development of modern political thought.

In contrast, Voltaire focused more on civil liberties and freedom of speech, while Hobbes is known for his views on social contract theory and the necessity of a strong central authority, asserting that a powerful sovereign is needed to avoid chaos. Rousseau, meanwhile, explored concepts of general will and direct democracy, which do not specifically pertain to the separation of powers. Montesquieu’s emphasis on dividing governmental authority was crucial for shaping the governance structures of many contemporary states.