Which document established the current governmental structure of the United States?

The U.S. Constitution is the foundational document that established the current governmental structure of the United States. Ratified in 1788, the Constitution outlines the framework of the federal government, delineating the powers and responsibilities of its three branches: the legislative, the executive, and the judicial. It also provides for a system of checks and balances to prevent any one branch from becoming too powerful.

The Constitution replaced the Articles of Confederation, which had created a weak central government that struggled to address the needs of the nation effectively. In doing so, the Constitution established a stronger national framework, which included provisions for a bicameral legislature and a process for amending the document to adapt to changing circumstances.

Additionally, while the Declaration of Independence is a crucial historical document that articulated the colonies' desire for independence from Britain, it does not set forth the structure of government. The Bill of Rights, which comprises the first ten amendments to the Constitution, is significant for enumerating individual rights but does not establish government structure itself. Therefore, the U.S. Constitution is the correct choice as it directly outlines the system of governance in the United States today.