Kritarchy, also called kritocracy, was the system of rule by Biblical judges (Hebrew: , shoftim) in ancient Israel, started by Moses according to the Book of Exodus, before the establishment of a united monarchy under Saul.
Because the name is a compound of the Greek words , krites ("judge") and ?, árkh? ("to rule"), its colloquial use has expanded to cover rule by judges in the modern sense as well. To contrast such a rule by (modern) judges with the actual form of the 1996 Constitution of the Republic of South Africa, judge Albie Sachs coined the term dikastocracy for it, from ("judge"), rejecting the coinage "juristocracy" for being an admixture of Latin and Greek.
Sachs and others rejected the idea that the Constitutional Court of South Africa, on which he sat, was a dikastocracy; using the name to denote what they asserted the Court not to be. It was used in a 1996 Court opinion that rejected the "horizontal" application (between citizens as opposed to "vertical" application between citizens and the government) of the RSA constitution's Bill of Rights and warned that "horizontal" application would turn the republic into such a dikastocracy.
Others have similarly used this as an inverse definition to denote what they assert their form of government is not. Supreme Court of the United States justice Stanley Forman Reed, the last dissenter to be convinced in the decision on Brown v. Board of Education used kritarchy as the name for the judicial activism that he initially dissented from, asking his clerk (John Fassett) who argued with the direction to write a dissenting opinion whether he (Fassett) favoured a kritarchy. Fassett was unfamiliar with the word, and Reed told him to look it up. Fassett could not find it in several dictionaries, finally locating it in the Oxford English Dictionary.
This form of rule (in the non-Biblical sense) is the case of Somalia, ruled by judges with the polycentric legal tradition of xeer. The definition employed by Michael van Notten (based upon one by Frank van Dun[page needed]) is not, strictly, that of rule by judges, judges not being a formal political class but rather people selected at random to perform that task ad hoc; but rather is that of a legal and political system whose closest analogue in other societies is that of a system based entirely upon customary rather than statutory law. Van Notten himself argues that with few exceptions, the system of government which he denotes a kritarchy is "harmonious with the concept of natural law" and "very close to what in philosophy might be called 'the natural order of human beings'".
Ireland had a system of kritarchy from the 5th century BCE to the 5th century CE under the Brehon Law, the Brehons being the class of Druid Judges. A kritarchy system was also present in medieval Ireland until the 13th century.