Hello. You did not present the text to which this question refers, which makes it impossible for it to be answered. However, I will try to help you in the best possible way.
It is only possible to know how the author developed the central idea of the text, after a reading of the text has been done. However, we can consider that:
If this is a fictional text, that is, a story invented by the author that did not happen in real life. The author developed the central idea by creating situations where the law was prevailed no matter what happened and was applied to anyone, even if that application seemed unfair.
If this is a non-fictional text, that is, a text that presents facts from real life, the author developed the central idea, presenting evidence that the law should stand out in any situation. Thus, the author may have presented real examples, about times when the law was applied without regard to the circumstances.