Ancient and Modern
Extremes of wealth, poverty or corruption make good subjects for historians because they are easy to discern. The man in the middle is often less easy to pick out, even during election times when 'middle England' is supposed to hold the key. Aristotle defined 'middle Greeks' broadly in terms of their wealth and desires, and saw them as a positive force for good.
Wedded to his doctrine of the 'mean' (i.e. that extremes should be avoided and the middle way was best), Aristotle reckoned that the best form of constitution was one in which 'middle people,' as he calls them, were dominant. Such people, being neither excessively rich nor excessively poor, avoided the vices of the wealthy (contempt for others and refusal to be ruled), and of the impoverished (envy and a servile mentality). Again, since they did not covet the possessions of others, as the poor did, and the rich did not covet theirs, they were secure.
Next, middle people were least reluctant to hold office, but also least eager to: Aristotle thought that both excessive desire for and excessive hostility to public service were 'detrimental to states'. Most important of all, a middling condition was one most people could aspire to: after all, 'the state aims to consist as far as possible of those who are like and equal, a condition found chiefly among the middle people.'
A state divided into two—which for Aristotle meant the poor and the rich—could never be at peace, because the differences would constantly set the two sides against each other. What was required was a state with a large middle ground—both for its own intrinsic virtue, and to defuse extremists on either flank. Only in this way could a state be secure, and free from division and faction.
So any politician who proposed extremes, e.g. that unlimited personal wealth creation was to be encouraged, would have struck Aristotle as dangerous. Aristotle was equally suspicious of any ideology which set its manifesto out in terms of supporting one section of society against another (he thought this was the problem with democracy, though he was not opposed in principle to collective decision-making). So, for example, he exhorted oligarchies to cultivate the poor and democracies the rich. Again, since Aristotle did not believe that people were naturally equal, he could not see why they should be treated equally: so what kind of superiority should qualify a person for power? Certainly not the random votes of citizens: power was far too important a prerogative for that. Good birth, ownership of property, and moral qualities like justice and courage were priorities. But even worse for our present incumbents, Aristotle believed that the purpose of the state was to enable its citizens to live well, which he defined not in terms of economics but of culture. A leader who did not himself live up to the highest standards of education and culture could not by definition develop a state in the required way.
Aristotle hinted that he favoured enlightened tyrants, but in their absence looked for a balance between oligarchy and democracy. He could well have approved of our system of elective oligarchy, if not of our leaders.