Oligarch n. : A member of an oligarchy; one of the rulers in an oligarchical government.

Example:
Has Bush decended to the level of the despotic Oligarch with no regard for rule of law?

Taxonomy
oligarchy, Iron Law of Oligarchy, rule, Articles with unsourced statements, free encyclopedia, Forms of government, wealth, Search, government, aristocracy, monarchy, society, English society, Ancient Greece, power-sharing, whites, military, Greek words.

Defination from the web:
... rule by the rich, for which the exact term is plutocracy, oligarchy is not always a rule by wealth, as oligarchs can simply be a privileged group. ...