“Suit yourself!”
All kidding aside, what do you mean by that? Do you not agree that natural right theory, or in the very least American natural right theory, is based on belief in God?
Of course natural law encompasses a belief in God, for those who choose to see it through that lens. But it is not “God’s law,” nor does it need “preachers” to expound upon it.
When two robins mate, they produce robins. When two Americans mate, they produce Americans.
That is the “nature” of things, pure and simple. One could say that is the “law of nature.”
No one needs a preacher (or a lawyer, for that matter) to reveal that robins birth robins and Americans birth Americans.
That is all.
Everything beyond that is made up by man and, thus, is not by operation of nature, but by operation of law.