Montesquieu was a French lawyer, man of letters, and one of the most influential political philosophers of the Age of Enlightenment. His political theory work, particularly the idea of separation of powers, shaped the modern democratic government.

He conceived the idea of separating government authority into the three major branches: executive, legislative and judicial. This perspective significantly influenced the authors of the Constitution in establishing laws and division of duties, and also in the inclusion of provisions to preserve individual liberties.

Baron de Montesquieu Accomplishments

• Formulated the principle of the separation of powers, a cornerstone of modern democracy.
• President of the Bordeaux Parliament, and additionally found success as a writer, lawyer and philosopher.
• His works inspired the US constitution.

Montesquieu took the view that the Roman Republic had powers separated so that no one could usurp complete power. In the British constitutional system, Montesquieu discerned a separation of powers among the monarch, Parliament, and the courts of law.

The Founding Fathers read the ideas of Enlightenment thinkers. They read John Locke’s work about natural law and the social contract, and Baron de Montesquieu’s work about separation of powers. The Founding Fathers included these ideas when they wrote the Declaration of Independence.

The founders of the United States were deeply influenced by republicanism, by Locke, and by the optimism of the European Enlightenment.

His political theory of government by the consent of the governed as a means to protect the three natural rights of “life, liberty and estate” deeply influenced the United States’ founding documents. His essays on religious tolerance provided an early model for the separation of church and state.