The Decline of Natural Law: How American Lawyers Once Used Natural Law and Why They Stopped
“We hold these truths to be self-evident…” is not how one would begin an argument in a courtroom these days. Nevertheless, thus begins the Declaration of Independence, appealing to the “laws of Nature and Nature’s God.” Its advocates could claim legal vindication — not just vindication on the field at Yorktown. What changed? Stuart Banner’s recent legal history, The Decline of Natural Law, sets out to answer that question.
Banner’s history begins before the change, describing a legal system based on natural law. Common law judges were not tasked with interpreting or making the law, as we would describe their job today — rather, they sought to find law. Law was found in the customs and traditions of the British people, as well as reasoning from principals of the law of nature. In the American context, when either the nature or habits of the American people did not support a traditional British legal doctrine, colonial judges could overturn it as contrary to reason and natural law.
The foundations of natural law jurisprudence would begin to show cracks with that second essential founding document — our Constitution. The Ninth Amendment notwithstanding, the existence of a written constitution began to undermine appeals to unwritten law. With an unwritten constitution, the only constraint on Parliament’s authority was natural law. But debates began about whether unwritten law could constrain the legislative power in a system with a written constitution. Natural law moved from the foundation of the legal system to a mere component of it.
After the founding generation, the change from a legal system with natural law to one without occurred throughout the 1800s. Banner locates the change in several concepts, including the inability of natural law theorists to come to consistent conclusions on things like slavery, women’s rights, and the death penalty. On all these issues, lawyers using freewheeling natural law concepts could come to contrary conclusions, and natural law began to appear as arbitrary.
Also fascinating is the role of legal publishing. The United States experienced an explosion of new case reporters in the late 1800s. Previously, an opinion, if written at all, was only evidence of what the law was. After, it became more common to say — as we do today — that the opinion is the law. Before, it was common to disparage a lawyer that exclusively quoted from cases as a “case lawyer” — one lacking in legal and moral intelligence. By the early 20th century, everyone was a case lawyer. There was no other way.
The disappearance of natural law, however, left a void. Ideas varied regarding how to ground law, from Justice Holmes saying all law is arbitrary, to other theorists looking to the history of the Anglo-Saxons. Perhaps the most durable replacement has been substantive due process. Banner points to Justice Kennedy’s opinion in Obergefell as a primary example of the principal-based moral reasoning that a lawyer using natural law-based arguments would have employed. So it is that natural law still exists. But certainly, as recent rulings would suggest, not on as sturdy a foundation as it once did.