Regarding the nature of "laws," and the idea that laws which work against the common good of souls are not to be obeyed, even the conciliarists recognize the principle as applied to the civil law.
This passage from Catholic Answers peretains to laws on abortion having no power to bind, to illustrate the principle:In our day, the most egregious example of the failure of civil authority to maintain the common good and protect human rights is in the legalization of abortion and euthanasia. Applying the Catechism’s teachings, Pope John Paul II wrote at length about civil disobedience in his encyclical, Evangelium Vitae (The Gospel of Life):
Laws which authorize and promote abortion and euthanasia are therefore radically opposed not only to the good of the individual but also to the common good; as such they are completely lacking in authentic juridical validity. Disregard for the right to life, precisely because it leads to the killing of the person whom society exists to serve, is what most directly conflicts with the possibility of achieving the common good. Consequently, a civil law authorizing abortion or euthanasia ceases by that very fact to be a true, morally binding civil law.https://www.catholic.com/magazine/print-edition/when-is-it-okay-to-disobey
Abortion and euthanasia are thus crimes which no human law can claim to legitimize. There is no obligation in conscience to obey such laws; instead there is a grave and clear obligation to oppose them by conscientious objection.
And here is St. Thomas Aquinas explaining again that laws which are not just are no laws at all (note that we are not yet speaking of human ecclesiastical laws; we are still just setting the foundations to discuss the nature of laws generally):As Augustine says (De Libero Arbitrio i, 5) “that which is not just seems to be no law at all”: wherefore the force of a law depends on the extent of its justice. Now in human affairs a thing is said to be just, from being right, according to the rule of reason. But the first rule of reason is the law of nature, as is clear from what has been stated above. Consequently every human law has just so much of the nature of law, as it is derived from the law of nature. But if in any point it deflects from the law of nature, it is no longer a law but a perversion of law. . . .Some things are therefore derived from the general principles of the natural law, by way of conclusions; e.g. that “one must not kill” may be derived as a conclusion from the principle that “one should do harm to no man”: while some are derived therefrom by way of determination; e.g. the law of nature has it that the evil-doer should be punished; but that he be punished in this or that way, is a determination of the law of nature.Accordingly both modes of derivation are found in the human law. But those things which are derived in the first way, are contained in human law not as emanating therefrom exclusively, but have some force from the natural law also. But those things which are derived in the second way, have no other force than that of human law.
—Summa Theologiae I-II:95:2
Is this same principle applicable against human ecclesiastical laws?
To be continued;
When we resume, we will continue with Suarez's De Legibus (about laws):
Book 1-On the Law in general, its causes and effects;
Book 2-On the Eternal Law, the Natural Law and the Law of Nations (Jus gentium);
Book 3-On the positive, man-made law, or the Civil Law (i.e., secular as opposed to ecclesiastical law); Book 4-On the positive ecclesiastical (or Canon) law;
Book 5-On the variety of human law, especially on penal (criminal) and onerous (i.e., tax) laws;
Book 6-On the interpretation, the changing and the cessation of positive human laws;
Book 7-On the unwritten law, which is also called customary law;
Book 8-On Privileges;
Book 9-On the Divine Law of the Old Testament; and
Book 10--On -the New Divine Law (i.e., that of the New Testament).