Time for me to go re-read 'The Republic'
http://en.wikipedia.org/wiki/The_Republic_(Plato)
The dialectical forms of government
Plato spends much of the Republic narrating conversations about the Ideal State. But what about other forms of government? The discussion turns to four forms of government that cannot sustain themselves: timocracy, oligarchy (also called plutocracy), democracy and tyranny (also called despotism).
Timocracy
Socrates defines a timocracy as a government ruled by people who love honor and are selected according to the degree of honor they hold in society. Honor is often equated with wealth and possession so this kind of gilded government leads to the people valuing materialism above all things.
Oligarchy
These temptations create a confusion between economic status and honor which is responsible for the emergence of oligarchy. In Book VIII, Socrates suggests that wealth will not help a pilot to navigate his ship. This injustice divides the rich and the poor, thus creating an environment for criminals and beggars to emerge. The rich are constantly plotting against the poor and vice versa.
Democracy
As this socioeconomic divide grows, so do tensions between social classes. From the conflicts arising out of such tensions, democracy replaces the oligarchy preceding it. The poor overthrow the inexperienced oligarchs and soon grant liberties and freedoms to citizens. A visually appealing demagogue is soon lifted up to protect the interests of the lower class. However, with too much freedom, the people become drunk, and tyranny takes over.
Tyranny
The excessive freedoms granted to the citizens of a democracy ultimately leads to a tyranny, the furthest regressed type of government. These freedoms divide the people into three socioeconomic classes: the dominating class, the capitalists and the commoners. Tensions between the dominating class and the capitalists causes the commoners to seek out protection of their democratic liberties. They invest all their power in their democratic demagogue, who, in turn, becomes corrupted by the power and becomes a tyrant with a small entourage of his supporters for protection and absolute control of his people.