Having explored the ideal state in De re publica, the great Roman statesman and lawyer Cicero turned his attention to its legal foundation in his dialogue De Legibus (On the Laws). In this work, Cicero sets out to draft the perfect legal code for an ideal republic. More importantly, he gives his most complete defense of the idea that true law is rooted not in utility or power, but in natural reason. This episode delves into Cicero’s mature legal philosophy, a masterful synthesis of Roman legal tradition and Greek Stoic thought. We analyze his famous argument that "true law is right reason in agreement with nature," a universal and unchanging principle. For Cicero, a statute that violates this natural law—even if passed by the people—is not a true law at all, but an act of injustice. De Legibus is a passionate defense of the rule of law against the threats of tyranny and mob rule that Cicero witnessed in the dying days of the Republic. It represents the pinnacle of Roman legal theory and has been a touchstone for legal thinkers for over two millennia. It is a timeless argument for a justice that transcends politics.