Few political ideals are praised as widely as the rule of law. Governments of every kind claim to respect it, which makes it worth asking what it actually requires. At its heart is a simple contrast: government by settled rules rather than by the will or whim of whoever holds power.

An old idea

The ideal is ancient. Aristotle argued that it is better for the law to rule than any single citizen, because even the best rulers are swayed by passion. In 1215 English barons forced King John to accept Magna Carta, which bound the king to proceed against free men only through lawful judgment or the law of the land. The charter was soon broken and reissued, but it became a lasting symbol of the idea that the ruler, too, is under the law.

Dicey's three meanings

The phrase was made famous by the English jurist A. V. Dicey in Introduction to the Study of the Law of the Constitution (1885). He gave it three meanings:

1. No arbitrary power. No one can be punished except for a definite breach of law, proved in the ordinary courts.
2. Equality before the law. Every official, from the highest minister to a tax collector, is subject to the same law and the same ordinary courts as any other citizen.
3. Rights from the courts. In England, Dicey said, the basic liberties came from judges deciding ordinary cases, not from a written charter.

Critics note that Dicey was dismissive of systems like France's, where special administrative courts hear cases against the state. Those courts often protect citizens well, so his third point now looks more like a description of England than a universal requirement.

Core principles today

Modern accounts usually list a set of principles that overlap with Fuller's list from Level 1:

• Generality. Laws should address kinds of people and conduct, not named individuals. A statute that declares a particular person guilty without trial violates this.
• Publicity. Laws must be published and accessible, so people can know them before they act. Secret law cannot guide anyone.
• Prospectivity and clarity. Laws should apply to the future, not punish what was lawful when done, and should be clear enough to follow.
• Equality before the law. The same rules apply to rich and poor, to officials and ordinary citizens.
• Independent courts. Judges need secure tenure and freedom from pressure, so that disputes, including disputes with the government, are decided by law rather than by power.

Thin and thick conceptions

Scholars disagree about how much the rule of law includes. A thin (or formal) conception focuses on the form of law, such as generality, clarity, publicity and consistent application, and says nothing about the content. A thick (or substantive) conception adds protection of basic rights and sometimes democracy. Defenders of the thin view say it keeps the idea precise and stops it from becoming a label for everything good. Defenders of the thick view reply that a system of clear, public rules that strip a minority of all rights hardly deserves the name.

Rule of law versus rule by law

A useful distinction separates the rule of law from rule by law. Under rule by law, rulers use law as a tool to control others while placing themselves above it. They may pass many statutes and hold many trials, but courts never rule against those in power. The real test of the rule of law is whether the powerful can lose a case.

Worked example: the mayor's parking tickets

Picture an invented city where a journalist discovers that the mayor's car has collected forty unpaid parking tickets, and that the city's parking office quietly cancels them each month. Meanwhile, ordinary drivers who fail to pay face towing and fines. Let us test this against the principles of this level.

• Equality before the law. This is the clearest failure. Dicey's second meaning holds that officials answer to the same law as everyone else. A mayor whose tickets disappear is above the rule that binds a delivery driver.
• Publicity. The parking rules are published, but the practice of cancellation is secret. In effect there is a hidden second rule: tickets do not apply to the powerful.
• Independent courts. Suppose a citizen sues to force the office to collect. Can a judge hear the case without fear of losing her post? If so, the system has a way to correct itself.

Now suppose the city council responds by passing an ordinance that says, “Tickets issued to the mayor's vehicle are void.” The practice is now public and written. A thin conception might note that the rule is at least open and clear, though it fails generality by singling out one office for privilege. A thick conception would condemn it more directly as unequal treatment.

The example is small, but the pattern is the one that matters most in large cases: the rule of law is tested when the people in charge are on the wrong side of a rule.