We want to remember that when our Founders wrote that "All men are created equal" they were writing as the aristocratic elite of the colonies. None of them was confused that some uneducated or otherwise unaccomplished person was their equal the way we tend to think of the term today. What they were attempting to do with our founding documents was justify to world opinion the reason for their treason. (They were, after all, launching open rebellion against recognized lawful authority, meaning that unjust rebellion wouldn't gain the sympathy of such entities as -- oh, I don't know ... say, France, for instance.) It was imperative to make a case for why they were doing something that was right, rather than merely opportunistic. Thus came to be written a short political tract (the Declaration of Independence) that was founded on very popular, well-known, quasi-Christian ideas of the time, namely: that nature and nature's God had fitted all human beings out with a rational faculty that made it possible for us to cope with the world as, apparently, the world really is (i.e., since our efforts to cope with the world seem to more-or-less work, we must be dealing with the world as it really is, QED). This quality of human rationality matching up with reality, made it a requirement that governments justify their acts on the basis of disembodied reason rather than mere power or tradition. The king was equal to the lowest knave in this sense.
It's in this sense (and only this sense) of endowment from nature of a universal rationality that all people (other than children or people with pathologies of one sort or another) are equal. All of us are equally fit for the rule of law because we can be reasoned with.