Fuller's Ways to Fail to Make Law

In The Morality of Law (Yale U. Press 1964), Fuller uses the allegory of Rex, an inept king, to illustrate eight ways to fail to make law:

(1) failure to achieve rules at all, so that every issue must be decided ad hoc;
(2) failure to publicize, or at least to make available to the affected party, the rules he is expected to observe;
(3) the abuse of retroactive legislation;
(4) failure to make the rules understandable;
(5) enactment of contradictory rules;
(6) enactment of rules that require conduct beyond the powers of the affected party;
(7) introducing such frequent changes in the rules that the subject cannot orient his action by them;
(8) failure of congruence between the rules as announced and their actual administration.

"A total failure in any of these eight directions does not simply result in a bad system of law; it results in something that is not properly called a legal system at all...Certainly there can be no rational ground for asserting that a man can have a moral obligation to obey a legal rule that does not exist, or that is kept secret from him...[etc.]."

"In situations like these there can be no simple principle by which to test the citizen's obligation of fidelity to law, any more than there can be such a principle for testing his right to engage in a general revolution. One thing is, however, clear. A mere respect for constituted authority must not be confused with fidelity to law. Rex's subjects, for example remained faithful to him as king throughout his long and inept reign. They were not faithful to his law, for he never made any."

So, a legal system has to have certain features in order to issue laws to which citizens have a moral obligation to be faithful. At the least, it needs to issue laws that are regular, public, prospective, understandable, not contradictory, possible to comply with, constant, and consistently administered. If its laws uniformly lack any of these features, citizens cannot have a duty of fidelity to them (presumably because "ought" implies "can"). But does the sum of these characteristics necessarily give rise to laws that are morally binding (or to which citizens have a duty of fidelity)? Couldn't the Nazis have issues some substantively reprehensible laws that met these criteria? This is what Fuller tries to deny in his response to Hart by declaring his belief that "coherence and goodness have more affinity than coherence and evil," but isn't some more substantial argument required to show how a duty of fidelity to law arises from mere process constraints?

See Lon Fuller's The Morality of Law (1964).