Who was the 4th president of the United States and ratified the Constitution?

James Madison, the 4th president of the United States, is often referred to as the "Father of the Constitution" because of his pivotal role in its drafting and ratification. He was instrumental in the deliberations at the Constitutional Convention in 1787 and is noted for his contributions to the Federalist Papers, which advocated for the ratification of the Constitution. Madison’s deep understanding of governmental structure and his commitment to a strong federal government highlighted his influence in shaping the framework of the U.S. government.

His presidency, which lasted from 1809 to 1817, followed his crucial involvement in the founding documents of the nation, further cementing his legacy as a key figure in American history. The other figures listed, while significant in their own right, do not hold the same dual significance in both the presidency and the Constitution's ratification.