United states constitution is the foundational legal document establishing the structure, powers, and limitations of the federal government of the United States and guaranteeing fundamental rights. As a major academic concept and research field, it is a central subject of inquiry in constitutional law, political science, and history, investigating its historical development, original meaning, evolving interpretation through judicial review and amendment, key structural principles (including separation of powers and federalism), and its enduring significance as the supreme law of the land, a framework for American governance, and a subject of continuous scholarly debate regarding its application and relevance.