The U.S. Constitution came into effect in 1789. After its drafting in 1787 during the Philadelphia Convention, the Constitution was ratified by the required nine states and officially established the framework for the United States government. This document created a federal system with checks and balances among the executive, legislative, and judicial branches. The Constitution has undergone amendments to reflect changes in society and has served as a model for democratic governance worldwide. It remains a cornerstone of American law and civic identity, symbolizing the principles of freedom and democracy.