Charles de Secondat, Baron de Montesquieu (1689­-1755), was a nobleman, a judge in a French court, and one of the most influential political thinkers. Based on his research he developed a number of political theories presented in The Spirit of the Laws (1748). The father of the United States Constitution, James Madison, once said, “the oracle who is always consulted and cited on this subject [separation of powers] is the celebrated Montesquieu.”.