The dimensions of the separation of powers principle are explored through three lessons in the subject areas of U.S. history, U.S. government, and world history. In 1748, a French nobleman, Baron de Montesquieu, wrote a book called "The Spirit of the Laws," in which he argued that there could be no liberty when all government power was held by one person or even one group of rulers. Montesquieu described a political system that separated power into three branches of government. He believed that a government based on the "separation of powers" plan would ensure liberty by preventing the establishment of an absolute ruler like Louis XIV. The impact of absolute rule is illuminated through a short discussion of the French Huguenots' oppression during the reign of Louis XIV. The principle of separation of powers is depicted through a discussion of the Radical Republicans in Congress and the impeachment proceedings against President Andrew Johnson. The last lesson focuses on the separation of powers in the U.S. government by reviewing the power to declare war. Even though Congress has declared war five times, U.S. soldiers have been sent into combat situations over 100 times by the President acting as commander-in-chief of the military. Each lesson is accompanied by an activity such as a debate or an historical trial. (SM)