Rule of law
Etymology
From “rule,” via Old French from Latin “regula,” “a straight stick, a ruler, a pattern,” from “regere,” “to keep straight, guide, rule.” The measuring-stick image is apt: the rule of law means a fixed, public standard against which all conduct — including the state’s — is measured, rather than a standard that bends to power.
noun phrase · /ROOL uv LAW/
The principle that everyone, including those in power, is bound by known, publicly applied laws rather than by arbitrary whim.
What it names
Use it to name the condition where law, not the ruler’s mood, governs — and applies to the ruler too.
Example
When the president simply ignored the court’s order, commentators said the rule of law itself was at stake.
Related idea
The rule of law means governing through general, predictable rules that bind the rulers; “rule by law” is its counterfeit — using law merely as a tool to control the governed while the powerful stay above it. The whole point is that no one is exempt.