Rule of law
Rule of law is the principle that every individual is subject to the law, including the law makers. Black's Law Dictionary defines it as, "the supremacy of regular as opposed to arbitrary power." According to Judge Richard Posner, “The rule of law means that judges decide cases ‘without respect of persons,’ that is, without considering the social status, attractiveness, etc. of the parties or their lawyers.”
Rule of law is a rebuke to rulers who argue that they are exempt from the law from due to divine right or other rationale. The concept was familiar to ancient philosophers such as Aristotle, who wrote "Law should govern." It was a principle followed during the Roman Republic. "We are all servants of the laws in order that we may be free," Cicero wrote. Roman magistrates had immunity from prosecution as long as they held office. But they could be held to account for any transgressions once their terms expired. (This system didn't cover senators since they were former magistrates who, at least in theory, merely advised their successors.) In imperial times, the emperor had full legal immunity (legibus solutus).
The Magna Carta of 1215 established the principle that the king of England is subject to the law. This may not have been the original intention of the document, but it has been consistently interpreted this way, most authoritatively by Sir Edward Coke. The phrase "rule of law" is found in a petition to King James I submitted by parliament in 1610. In the English Civil War (1642–1651), the king asserted that his "divine right" took precedence over the law. Samuel Rutherford argued for rule of law in Lex, Rex: The Law is King (1644), while Robert Filmer defended divine right in Patriarcha (1680).