Author of The Spirit of the Laws, proposer of the separation of powers
A French Enlightenment thinker. In his great work The Spirit of the Laws he proposed the core design adopted by countless nations thereafter: to divide state power into legislative, executive, and judicial parts, keeping them independent and mutually checking. His reasoning was starkly clear — "every man invested with power is apt to abuse it, this is an eternal experience" — so the only reliable way is not to hope that rulers are virtuous, but to "check power with power." This thought became the skeleton of the U.S. Constitution and of modern constitutionalism.
Montesquieu trusted no one to be entrusted with sole power. He said: to prevent the abuse of power, power must be divided and made to check itself — legislative, executive, and judicial each minding their own, none able to cover the sky with one hand. This "check power with power" was taken by America’s founders as a maxim, written into the Constitution, and became the most basic and most important principle in the design of modern political systems.
Below are how modern works borrow or reinterpret this name or story — not the original material. The two differ, so keep them apart.