You may doubt, but how can you argue with
The Declaration Of Independence, which justifies the sovereign independence of the original States, based upon Natural Law premises. These were carried forward in a Constitution, which deals functionally with realities of human nature, which the Founders clearly recognized as reflecting the Laws of Nature.
Actually, the very dedication in the Preamble, recognizing "Liberty" as a "Blessing," and their purpose as multi-generational, reflects Natural Law as providing the foundation for the sort of political societies that they sought.
William Flax