Which Enlightenment thinker is also known for the idea of checks and balances in government?

Baron de Montesquieu is well-known for his concept of checks and balances within government systems. His work, particularly "The Spirit of the Laws," advocated for the separation of powers into distinct branches: legislative, executive, and judicial. Montesquieu argued that this separation was essential to prevent any one branch from becoming too powerful and thus protect individual liberties. His ideas significantly influenced modern democratic theory and the design of government structures, especially in the formation of the United States Constitution.

In contrast, John Locke focused primarily on natural rights and the social contract, asserting that government is established to protect individuals' rights to life, liberty, and property. Voltaire is best known for his advocacy of civil liberties, particularly freedom of speech and separation of church and state, rather than the structural organization of government. Rousseau concentrated on the concepts of popular sovereignty and the general will, emphasizing the role of the collective in governance rather than checks and balances among branches. Therefore, Montesquieu’s specific proposal for a system of checks and balances is what distinctly identifies him in this context.