Your wording is pretty revealing:

> This framework creates a moral basis to rights

The Constitution (and the thinkers that it was based off of) creates a moral basis to rights. At the time the Constitution was written, this was a pretty radical idea. The most prevalent moral framework at the time was the divine right of kings, the idea that the king was ordained by God to rule and anyone who questioned that right was speaking heresy.

My wording was actually wrong, as the constitution recognizes a divine source for the rights, it doesn't create the moral basis. Perhaps 'establishes as the formal basis' would have been more appropriate.

You're right that it was a relatively radical idea at the time, but not without precedent. The Dutch, Venice and Genoa were republics, the Swiss Confederation was a union of cantons and territories, for example, not to mention the influence of the Iroquois Confederacy, John Locke, Montesquieu, and the assorted Greek and early Roman city states.