Who is considered the principal author of the United States Constitution?

James Madison is often regarded as the principal author of the United States Constitution due to his central role in its drafting and his extensive contributions to the Federalist Papers, which were pivotal in promoting the ratification of the Constitution. Madison’s political philosophy and insights significantly influenced the structure and principles of the Constitution. He is frequently referred to as the "Father of the Constitution" because of his significant involvement in the Constitutional Convention of 1787 and his efforts to ensure that the document reflected the ideals of a robust federalism.

His advocacy for a strong central government and a system of checks and balances helped shape the final document, which balanced the powers of the different branches of government. Madison also kept detailed notes during the Constitutional Convention, providing valuable historical insight into the discussions and debates that shaped the Constitution. This combination of drafting, theorizing, and advocating for the Constitution grants him a prominent position in its authorship.