Bailyn's fundamental starting point is that aspects of American History such as the Revolution and the Constitution emerged from an ideological reality shared amongst the Framers. Bailyn believes that in both public and private realms, specific ideas that espoused freedom and rights and spewed disdain towards tyranny and oppression helped to form the nation:
And that leads to this whole expansion of their [the framers'] ideological commitments, as they grope to explain what it is they're trying to preserve and what it is they're trying to oppose. So that by the time you get to 1776, there's an elaborate structure of thought that's worked out that justifies this and that really sets American constitutional thought on its path.
For Bailyn, "American constitutional thought" emerges from the "expansion of" the framers' ideological commitments. Ideas, not social conditions, generated the creation of the United States Constitution.
Zinn disagrees. He believes that the presence of material reality and the desire to accumulate more of it existed at the base of American identity construction. In both the American Revolution and the Constitution that followed, Zinn argues that the desire to appropriate individual wealth is what enabled the Constitution to be created. The denial of voice that the "framers," wealthy and privileged white men, imposed on women, people of color, and poor people are what Zinn uses to support his thesis. The only "idea" that the Colonists revered was power. This is in stark contrast to the Bailyn's thinking.