The Rule of Law Has Eight Marks, and Lawmakers Can Fail at Every One

Once upon a time, a king named Rex came to the throne and resolved to be a great lawgiver. This is the opening of one of the best-known thought experiments in twentieth-century legal philosophy, and I will tell it the way Lon Fuller did, because it makes a point that most civics classes miss. Rex tried to make law and failed eight different ways, one after another, and each failure was a way of ceasing to govern by law at all.

First he decided to scrap the muddle of precedent and decide each case as it came. Nobody knew what to expect. Then he drafted a code but kept it secret. Then he made it retroactive, so people were punished for what had been legal when they did it. Then he wrote it so that nobody could follow it. Then it contradicted itself. Then it demanded things no subject could do. Then he revised it daily. Finally, he and his officials simply ignored the code when it suited them. By the end of the story, the kingdom had no law, though it had plenty of orders. Rex had mistaken the production of text for the making of law.

It is a fable, and I will say so: Rex is an invention of Fuller's, not a real king. But every item on his list has a real-world history, and every item can be tested against what we hold today. Here is the list, the history behind each, the constitutional rule that answers it, and a hard question about the volume of rules we live under.

Where the list comes from

Lon L. Fuller, a professor at Harvard Law School, published The Morality of Law in 1964. It grew out of a famous debate with H. L. A. Hart, the Oxford legal positivist, in the Harvard Law Review in 1958. Hart had argued that law and morality are conceptually separate. Fuller replied that law has an inner morality: there are conditions a system must meet to count as law at all, and those conditions are moral in character, because they respect the person's dignity as a being who can follow rules and plan his life.

He identified eight. He called them "desiderata" and spoke of eight ways to fail to make law. A ruler can fail at some of them and still have a legal system, imperfect but recognizable; a ruler who fails completely at any one, Fuller says, ends up with something "not properly called a legal system at all."

Fuller's list sits alongside the older accounts of Albert Venn Dicey, who in Introduction to the Study of the Law of the Constitution (1885) described the rule of law as the supremacy of regular law over arbitrary power and the equality of all before the ordinary courts, and of Friedrich Hayek, who in The Road to Serfdom (1944) and The Constitution of Liberty (1960) argued that a free people must be governed by known, general rules. To anchor it in history, see The Rule of Law Is Older Than the Constitution, From Magna Carta to Marbury. Now, the eight.

Mark one: there must be rules

The first requirement is that the ruler govern through general rules rather than decide each case on its own. A rule says: everyone in this class of situations is to be treated this way. An ad hoc decision says: this man, today, gets this.

History is full of the failure. Under a court like the English Star Chamber, which sat until its abolition in 1641, or under a king's "prerogative" justice, a subject could not know what the standard was because there was no standard, only the judgment of those in power. The Constitution's answer is built into its structure. Article I vests the legislative power in Congress, a body that makes general laws for the whole country, and Article I, Section 9 forbids bills of attainder: legislative acts that single out a named person for punishment. That is the ban on the pure case-by-case decree, the "law" with one name on it.

Mark two: the rules must be published

A secret law is not a law; it is a trap. How can a person obey a command he cannot find? The ancient examples are grim. The Roman biographer Suetonius reports that the emperor Caligula first announced new taxes without publishing them in writing, so that many people broke the law unknowingly, and then had the law posted in a cramped spot in very small letters so that no one could copy it.

The Anglo-American tradition treats promulgation as basic. The Constitution requires each house of Congress to keep a journal of its proceedings and publish it, "excepting such Parts as may in their Judgment require Secrecy" (Article I, Section 5). Before 1935 there was no central place where rules with the force of law had to be filed and published, a gap exposed by the "hot oil" litigation of 1934 and 1935 (Panama Refining Co. v. Ryan) and by Erwin Griswold's article "Government in Ignorance of the Law" in the Harvard Law Review in December 1934. Congress answered with the Federal Register Act of 1935, and the first daily Federal Register appeared in March 1936. That is the point of a public register: to make it possible to find what you are required to do.

Mark three: no retroactive rules

The third is that rules must be prospective, not retroactive. A law that changes the past punishes a man for acts that were lawful when done. It is the cruelest form of surprise, because no amount of prudence can protect against it.

The Constitution says no, twice, for criminal law. Article I, Section 9 provides that "No Bill of Attainder or ex post facto Law shall be passed" by Congress, and Section 10 imposes the same ban on the states. In Calder v. Bull (1798), the Supreme Court held that the Ex Post Facto Clauses apply to criminal laws and not to civil ones, which is a narrower rule than Fuller's, but the principle that you cannot be convicted for an act that was innocent when you did it is common to every free country. Fuller allowed that retroactive curative statutes, which fix a defect in a past transaction, are sometimes necessary, and his objection is to retroactivity as a general policy.

Mark four: the rules must be understandable

A law that cannot be understood is a command in a foreign language. The American doctrine of "void for vagueness" is the legal form of this requirement. In Connally v. General Construction Co. (1926), the Supreme Court held that a law is void when it is so vague that "men of common intelligence must necessarily guess at its meaning and differ as to its application." The Due Process Clauses of the Fifth and Fourteenth Amendments demand fair notice.

The reason is not just fairness. A vague law shifts the real decision from the legislature to whoever enforces it. If a statute can mean anything, the prosecutor decides what it means, and a people ruled that way are ruled by prosecutors and not by laws.

Mark five: the rules must not contradict each other

If two rules require opposite things, a citizen who obeys one violates the other. Picture, as a labelled hypothetical, a small business owner told by one agency to post a notice in a particular place and by another that the same place must be kept clear. Both are enforceable. He cannot win. Contradictions can arise between different levels of government, between agencies, or inside a single statute.

The Constitution's answer to the federal-state version is the Supremacy Clause in Article VI, which makes federal law supreme over conflicting state law and so settles at least one class of conflicts. The answer to contradictions among federal rules is harder, and it lies in the courts' habit of reading statutes harmoniously and in Congress's duty to clean up its own work, a duty it seldom discharges.

Mark six: the rules must not demand the impossible

A law that commands what cannot be done is a mockery. The old maxim was lex non cogit ad impossibilia: the law does not compel the impossible. Fuller's example is a law that requires compliance with a standard that no one can meet, which leaves enforcers free to punish anybody they please, since everybody is in violation.

Rule-writers rarely intend impossibility. It creeps in through the accumulation of requirements, each reasonable on its own, that together exceed any person's capacity to comply. This is a matter of degree, and it is among the most underrated problems in modern regulation.

Mark seven: the rules must not change constantly

If the rules change every day, nobody can plan. A farmer who plants in the spring on the basis of the rules then in force, and finds by harvest that the rules have been rewritten, is ruled by caprice. James Madison said the same thing in Federalist 62, in one of the greatest sentences ever written on the subject:

It will be of little avail to the people, that the laws are made by men of their own choice, if the laws be so voluminous that they cannot be read, or so incoherent that they cannot be understood; if they be repealed or revised before they are promulgated, or undergo such incessant changes that no man, who knows what the law is to-day, can guess what it will be to-morrow.

Read it twice. In one sentence Madison catches four of Fuller's marks, volume, incoherence, publication and constant change, a century and a half before Fuller. See Federalist 62 Warned That Mutable Laws Betray a Free People. And Madison's point goes deeper than convenience: a law that cannot be known or relied on is not a law made by "men of their own choice" in any meaningful way. The people may have elected the lawmakers, and still not be self-governing.

Mark eight: officials must follow the rules as written

The last mark is the one that holds the rest together: congruence between the rule as declared and the rule as administered. Rex's final failure was to promulgate a code and then decide as he pleased. A system in which officials treat the written law as a suggestion, enforcing it against enemies and ignoring it for friends, is not governed by law.

This is the reason the American tradition treats the independence of judges, the jury and the requirement that executive officials act within statutory authority as central. The President's duty is to "take Care that the Laws be faithfully executed" (Article II, Section 3). The word faithfully carries the point. See Jury Duty Is the Rule of Law in Your Own Town, So Answer the Summons for the citizen's part in keeping officials to the text. And selective enforcement, whichever party practices it, is a violation of this mark.

The volume problem

Now to the hard question. Madison's list begins with the word "voluminous." Fuller's marks of clarity, consistency, possibility and stability are all strained by sheer volume. How much law is too much?

Here are two facts from the public record. By the Competitive Enterprise Institute's count of Federal Register data, the Register carried 2,441 final rules in 2025 and 3,248 in 2024. These are the binding regulations, issued by agencies under authority Congress delegated, that come on top of the statutes themselves. Final rules are not all the same size or weight, and many are routine, so the count is only a rough measure, but the direction of the argument is clear: the number of binding rules in a year is in the thousands.

Consider what that does to a person trying to follow the law. In Fuller's terms, a code of this size challenges clarity, because no one can read it; consistency, because rules written by different agencies at different times will overlap; possibility, because compliance with every requirement of a complex business may be beyond anyone's capacity; stability, because the rules keep changing; and congruence, because with so many rules, enforcement must be selective, and selection means discretion. Take them all together and the ordinary citizen, and especially the small business, cannot know with confidence whether he is breaking the law. The result is a world that Fuller would have recognized as lawless in his technical sense, despite the volume.

Large firms have lawyers and compliance departments; small ones do not. That is why regulation is often a barrier to entry, and why some big companies welcome it. See big companies love the regulations their small rivals cannot afford and the site's red tape page.

The strongest objection, answered

The best objection is that a modern economy is complicated and requires complicated rules. You cannot regulate airline safety, drug approval or financial markets with a few general principles. And Congress cannot write every detail, so it delegates to agencies, which is the only workable arrangement. Fuller's marks are an ideal, not a program.

Four replies.

1. Complexity is not the same as volume or caprice. A long statute that is clear, published, prospective and stable can satisfy every one of the eight marks. The problem is not length but the failure of each mark.
2. Delegation is where the marks are most at risk. When Congress writes a broad grant of authority and leaves the real rules to an agency, the rules that result are made by officials rather than by an elected body, can be revised by the next administration, and are written under pressure from interested parties. That is why the Supreme Court's decision in Loper Bright Enterprises v. Raimondo (2024), which ended the practice of deferring to agencies' readings of ambiguous statutes under Chevron, mattered: it returns the question of what the law means to judges, who must apply the text. See Roscoe Pound Warned the Bar About Administrative Absolutism in 1938 and A Regulatory Budget Would Make Washington Count the Cost of Its Rules.
3. The remedy is not to abandon the rules but to adopt practices that serve the marks: sunset clauses, regulatory budgets, a requirement that Congress vote on major rules, and plain-language drafting.
4. Even if the ideal is unreachable, the direction matters. A free people measures its government against a standard and asks it to move toward it.

The verdict: complexity is a reason to work harder at the eight marks, not an excuse to forget them.

The case in brief

1. Lon Fuller's The Morality of Law (1964) lists eight ways a ruler can fail to make law: no general rules, secret rules, retroactive rules, unintelligible rules, contradictory rules, impossible rules, constantly changing rules, and officials who do not follow the rules as written.
2. The Constitution answers several directly: the bills of attainder and ex post facto bans, the Supremacy Clause, the Take Care Clause and the guarantee of due process, and Madison in Federalist 62 warned of laws too voluminous to read and too changeable to know.
3. Each failure is a way of replacing law with the will of whoever holds power, whatever the form.
4. The sheer volume of binding rules, 2,441 final rules in 2025 and 3,248 in 2024, strains every one of the marks, especially for those who cannot afford lawyers.
5. The remedy is to hold lawmakers to the standard: write fewer, clearer, steadier rules, and have Congress, not agencies, own the consequential ones.

What you can do: open the Federal Register or the site's red tape page, pick one rule that affects a business in your town, and ask yourself which of the eight marks it meets; then write to your representative with the answer.