Jefferson wrote the Declaration of Independence; Madison wrote not only the United States Constitution, or at least most of it, but also the most searching commentary on it that has ever appeared. Each of them served as president of the United States for eight years. What they had to say to each other has to command attention.

In this quote, Edmund Morgan emphasizes the intellectual and historical significance of the relationship between Thomas Jefferson and James Madison, two of the most influential figures in the early history of the United States. Morgan highlights that Jefferson wrote the Declaration of Independence, a foundational document that articulated the colonies’ desire for independence, while Madison not only contributed significantly to the creation of the U.S. Constitution but also wrote extensive commentary on it, making him a key figure in American political thought. The quote points to the importance of their exchange of ideas, suggesting that their views on the country’s formation and governance are essential to understanding the development of the U.S. system.

The mention of both Jefferson and Madison serving as president of the United States for eight years serves to underline their deep involvement in the practical as well as the theoretical aspects of American governance. Their presidencies were not just periods of leadership but also times of significant influence on the direction of the nation. By framing their interaction as one of critical importance, Morgan suggests that their views and debates about governance, freedom, and the structure of the new republic hold enduring value for understanding the U.S. Constitution and its principles.

Morgan’s emphasis on the dialogue between Jefferson and Madison highlights that the two men were not just important as individual figures but also as key collaborators in shaping the nation. The conversation between them—whether through written correspondence or political cooperation—has had a profound impact on the country's political and legal systems. Their interactions were vital in shaping the ideological underpinnings of the U.S. government and the democratic principles that continue to influence American society.

In conclusion, Morgan’s quote underscores that the ideas and discussions between Jefferson and Madison have enduring relevance, and their contributions to the founding of the United States cannot be understated. Their perspectives on governance, law, and the nature of freedom are integral to understanding the foundations of American democracy, making their writings and correspondence essential for anyone studying U.S. political history.