Plato, Laws 739a

ἡ δὴ τὸ μετὰ τοῦτο φορά, καθάπερ πεττῶν ἀφʼ ἱεροῦ, τῆς τῶν νόμων κατασκευῆς, ἀήθης οὖσα, τάχʼ ἂν θαυμάσαι τὸν ἀκούοντα τὸ πρῶτον ποιήσειεν· οὐ μὴν ἀλλʼ ἀναλογιζομένῳ καὶ πειρωμένῳ φανεῖται δευτέρως ἂν πόλις οἰκεῖσθαι πρὸς τὸ βέλτιστον. τάχα δʼ οὐκ ἄν τις προσδέξαιτο αὐτὴν διὰ τὸ μὴ σύνηθες νομοθέτῃ μὴ τυραννοῦντι· τὸ δʼ ἔστιν ὀρθότατον εἰπεῖν μὲν τὴν ἀρίστην πολιτείαν καὶ δευτέραν καὶ τρίτην,

The next move in our settling of the laws is one that might at first hearing cause surprise because of its unusual character—like the move of a draughts-player who quits his sacred line ; none the less, it will be clear to him who reasons it out and uses experience that a State will probably have a constitution no higher than second in point of excellence. Probably one might refuse to accept this, owing to unfamiliarity with lawgivers who are not also despots: but it is, in fact, the most correct plan to describe the best polity, and the second best, and the third, and after describing them to give the choice to the individual who is charged with the founding of the settlement.