What document serves as the foundation for U.S. government?

The Constitution serves as the foundation for the U.S. government because it establishes the framework for the nation's legal and political structure. It outlines the three branches of government—executive, legislative, and judicial—and delineates the powers and responsibilities of each branch. The Constitution also provides the mechanisms for checks and balances, ensuring that no single branch can dominate the others, and articulates the fundamental rights of citizens through various amendments.

In contrast, the Declaration of Independence, while significant in asserting the colonies' desire for independence from British rule, does not establish a governing framework or system; rather, it outlines philosophical principles of liberty and individual rights. The Articles of Confederation served as the first governing document but proved ineffective and was eventually replaced by the Constitution due to weaknesses in federal authority. The Bill of Rights complements the Constitution by specifying individual liberties but does not form the structural basis of government itself. Therefore, the Constitution is recognized as the enduring document that not only created the government but also continues to guide its operation today.