Montesquieu

French political philosopher — author of The Spirit of the Laws (1748) — who developed the doctrine of separation of powers, argued that climate affects political systems, and created comparative government as an analytical discipline — whose work directly influenced the US Constitution.

Creates the doctrine of separation of powers — Montesquieu's Spirit of the Laws' analysis of the English constitution produced the separation of executive, legislative, and judicial powers that the American Founders adopted as their constitutional framework; the US Constitution's structure is directly derived from his analysis.