- Britannica:
The iron law of oligarchy, sociological thesis according to which all organizations, including those committed to democratic ideals and practices, will inevitably succumb to rule by an elite few (an oligarchy). The iron law of oligarchy contends that organizational democracy is an oxymoron. Although elite control makes internal democracy unsustainable, it is also said to shape the long-term development of all organizations—including the rhetorically most radical—in a conservative direction.
- Wikipedia:
The iron law of oligarchy is a political theory first developed by the German-born Italian sociologist Robert Michels in his 1911 book Political Parties. It asserts that rule by an elite, or oligarchy, is inevitable as an "iron law" within any democratic organization as part of the "tactical and technical necessities" of the organization.
Michels' theory states that all complex organizations, regardless of how democratic they are when started, eventually develop into oligarchies. Michels observed that since no sufficiently large and complex organization can function purely as a direct democracy, power within an organization will always get delegated to individuals within that group, elected or otherwise. As he put it in Political Parties, "It is organization which gives dominion of the elected over the electors. [...] Who says organization, says oligarchy."
In 1911 using anecdotes from the histories of political parties and trade unions struggling to operate democratically, Michels considered his argument applicable to representative democracy at large. He believed that "[h]istorical evolution mocks all the prophylactic measures that have been adopted for the prevention of oligarchy."
