Which historical document did James Madison primarily contribute to in 1787?

James Madison's primary contribution in 1787 was to the United States Constitution, which he helped draft and promote during the Constitutional Convention. Often referred to as the "Father of the Constitution," Madison played a crucial role in shaping the framework of the government that is still in use today. His influence included the development of key concepts such as the separation of powers and checks and balances, which are fundamental principles of the Constitution. Additionally, Madison authored a significant number of the Federalist Papers, which were instrumental in advocating for the ratification of the new Constitution. This foundational document laid the groundwork for American governance and replaced the Articles of Confederation, addressing the latter's weaknesses.