Which document establishes the foundation of the U.S. government?

The Constitution is the document that establishes the foundation of the U.S. government. It outlines the structure of the federal government, delineates the powers and responsibilities of its branches—executive, legislative, and judicial—and provides a framework for the functioning of the government. The Constitution also incorporates principles such as separation of powers and checks and balances, which are designed to prevent any one branch from becoming too powerful.

Additionally, it establishes the rule of law and protects individual rights, although the specific protections for individual rights are more explicitly detailed in the Bill of Rights, which consists of the first ten amendments to the Constitution. While the Articles of Confederation served as the first governing document for the United States, they proved to be ineffective due to the lack of a strong central authority, leading to the creation of the Constitution. The Declaration of Independence serves to announce the colonies' separation from British rule and lays the philosophical groundwork for government but does not establish the framework for governance itself.