Montesquieu

Charles-Louis de Secondat, Baron de La Brède et de Montesquieu (; French: [mɔ̃tɛskjø]; 18 January 1689 – 10 February 1755), generally referred to as simply Montesquieu, was a French judge, man of letters, historian, and political philosopher.
He is the principal source of the theory of separation of powers, which is implemented in many constitutions throughout the world. He is also known for doing more than any other author to secure the place of the word "despotism" in the political lexicon. His anonymously published The Spirit of the Laws (1748), which was received well in both Great Britain and the American colonies, influenced the Founding Fathers of the United States in drafting the U.S. Constitution.