The historical document adopted on September 17, 1787, is the United States Constitution. This foundational text established the framework for the U.S. government and delineated the rights of its citizens. The Constitution was the product of the Constitutional Convention held in Philadelphia, where delegates debated and drafted a plan to replace the Articles of Confederation. Ratified by the states in 1788 and becoming effective in 1789, it established a system of checks and balances among the three branches of government. The document remains a cornerstone of American democracy and law, influencing the development of constitutional governance worldwide.