It may help to an understanding of the Politics if something is said on those two points.
We are accustomed since the growth of the historical method to the belief that states are "not made but grow," and are apt to be impatient with the belief which Aristotle and Plato show in the powers of the lawgiver. But however true the maxim may be of the modern nation state, it was not true of the much smaller and more self-conscious Greek city. When Aristotle talks of the legislator, he is not talking in the air. Students of the Academy had been actually called on to give new constitutions to Greek states. For the Greeks the constitution was not merely as it is so often with us, a matter of political machinery. It was regarded as a way of life. Further, the constitution within the framework of which the ordinary process of administration and passing of decrees went on, was always regarded as the work of a special man or body of men, the lawgivers. If we study Greek history, we find that the position of the legislator corresponds to that assigned to him by Plato and Aristotle. All Greek states, except those perversions which Aristotle criticises as being "above law," worked under rigid constitutions, and the constitution was only changed when the whole people gave a commission to a lawgiver to draw up a new one. Such was the position of the AEsumnetes, whom Aristotle describes in Book III. chap, xiv., in earlier times, and of the pupils of the Academy in the fourth century. The lawgiver was not an ordinary politician. He was a state doctor, called in to prescribe for an ailing constitution. So Herodotus recounts that when the people of Cyrene asked the oracle of Delphi to help them in their dissensions, the oracle told them to go to Mantinea, and the Mantineans lent them Demonax, who acted as a "setter straight" and drew up a new constitution for Cyrene. So again the Milesians, Herodotus tells us, were long troubled by civil discord, till they asked help from Paros, and the Parians sent ten commissioners who gave Miletus a new constitution. So the Athenians, when they were founding their model new colony at Thurii, employed Hippodamus of Miletus, whom Aristotle mentions in Book II, as the best expert in town-planning, to plan the streets of the city, and Protagoras as the best expert in law-making, to give the city its laws. In the Laws Plato represents one of the persons of the dialogue as having been asked by the people of Gortyna to draw up laws for a colony which they were founding. The situation described must have occurred frequently in actual life. The Greeks thought administration should be democratic and law-making the work of experts. We think more naturally of law-making as the special right of the people and administration as necessarily confined to experts.
Aristotle's Politics, then, is a handbook for the legislator, the expert who is to be called in when a state wants help. We have called him a state doctor. It is one of the most marked characteristics of Greek political theory that Plato and Aristotle think of the statesman as one who has knowledge of what ought to be done, and can help those who call him in to prescribe for them, rather than one who has power to control the forces of society. The desire of society for the statesman's advice is taken for granted, Plato in the Republic says that a good constitution is only possible when the ruler does not want to rule; where men contend for power, where they have not learnt to distinguish between the art of getting hold of the helm of state and the art of steering, which alone is statesmanship, true politics is impossible.