In the aftermath of World War II, the victorious nations wrestled with how to prosecute Nazis accused of war crimes, igniting a debate over the source of law. One side said law was based on something everyone would know to be true about the world if they were not swayed by previous commitments or views of law. This idea is called natural law, and it goes back to the descriptions of humans as image-bearers of God in the Bible, to the Mosaic law, and the Christian theology of Thomas Aquinas (1225-1274), as well as various secular thinkers. When it comes to human rights, natural law says that people’s rights are “inherent,” meaning everyone has them without having to prove they are worthy of them.
According to natural law, a just society ought to secure the permanent rights of every person. In America, these rights are threefold: “life, liberty and the pursuit of happiness.” No person may be separated from these rights without due process of law, as spelled out in the US Constitution. The Constitution’s preamble makes clear the founders’ conviction that government didn’t grant the blessings of liberty but merely secured them. As the Declaration of Independence put it, those rights came from “Nature and Nature’s God.”
Such rights may not be taken away without due process of law. That each person has inherent rights is why, when someone is charged with a crime, the legal elements must be proved beyond a reasonable doubt before that individual’s rights and freedoms can be taken away.
Not everyone agrees with the inherent-rights view. Those advocating “legal positivism” say that justice does not have its source in God.¹ Rather, justice is whatever people in that society say it is. Societies’ leaders are to discern what a “better” society is and then use the tools of law to make society function smoothly for as many people as possible. Often those holding this view treat justice as if it is not about the treatment of individual people but about how groups of people relate in a well-ordered society. It is why governments increasingly express a willingness to remove rights from one group to reward them to another group, in the interests of order and fairness.
The Nazis on trial after World War 2 took full advantage of the disagreement between the natural law and the legal positivist camps. When confronted with evidence of their mass murder of millions of people, they said, “You have no right to judge us. We acted legally, based on the laws we were ordered to follow.” Legal-positivism advocates were in a quandary. If they argued that law was based on what those in authority decided, they would be granting that they had the right to judge the Nazis only because the Nazis lost. This implies that, had the Nazis won, the Nazi cause would have to be acknowledged as just, giving them, in turn, the moral authority to judge allied nations.
Natural law advocates face no such quandary. They argue that every human being knows it’s wrong to kill people en masse just because their leader tells them to. The Nazi leaders should have known better, regardless of what the Nazi government’s laws said.
Natural law advocates are suspicious of laws hastily made in a spirit of revenge. Instead, natural law advocates ask, “What laws should be passed to reflect what we know to be true in the natural law?” They would then identify what laws might need to be written or adjusted, or what people should be removed from positions of authority.