From the Buddhist perspective, I believe, as with all things, the only aim of government, regardless of the form, should be harmony. As for everything else, it doesn't really matter because of impermanence. Harmony helps us to maintain the precepts, everything else is superfluous and will pass away in time.
The closest we can come to a formulaic Buddhist political philosophy I believe, were the seven conditions for a nation's welfare the Buddha provided to Vassakara in the Mahaparinibbana Sutta:
1. Assemble and disperse peacefully,
2. Attend to your affairs in concord,
3. Neither enact new decrees nor abolish existing ones, but proceed in accordance with your ancient constitutions,
4. Show respect, honour, esteem, and veneration towards your elders and think it worthwhile to listen to them,
5. Refrain from abducting women and maidens of good families and from detaining them,
6. Show respect, honour, esteem, and veneration towards your shrines, both those within the city and those outside it, and do not deprive them of the due offerings as given and made to them formerly,
7. Duly protect and guard the arhats, so that those who have not come to the realm yet might do so, and those who have already come might live there in peace.
If anything, however, democracy can really hinder the adherence to these conditions. Especially if the state is not inclined to show respect to religious shrines, and if it is inclined to create new laws as the people change their minds all the time. Clearly, there is a reason why the Cakravartin isn't a principle, but a person, a monarch, whom the Dharma inspires, and is upheld.
By no means are we talking about autocracy either, since condition 1 and 2 would require meetings. In other words, I think we are looking at a constitutional monarchy - that is to say, a monarchy which abides by a set of pre-ordained principles and rules. The British model, is a great example I believe, where the Queen is both defender of the faith and constitution. All you need is more polite and concordant debate in the House of Commons.
As with anacyclosis, the Buddha recognises the need to protect the way of doing things in the past, "Neither enact new decrees nor abolish existing ones, but proceed in accordance with your ancient constitutions." Every civilisation has it's own way of doing things, and that tends to be what is best suited to their people's temperament. To suppose that one approach is suitable for everyone, is to be quite culturally arrogant. While idealism may make one believe that things are better off after revolutions, harmony tends to dwindle too because people lose ancient and well established, tried and tested ways of dealing with one another. There are accounts of social behaviour prior to and after the French revolution, where all manners had disappeared. Similarly in Russia, where today, after a century of turmoil due to idealism, you can't even drive down the street without encountering an unwieldy dose of aggression which ancient customs develop to avoid. Even more so in China, where the differences can easily be seen just by travelling to and from Taiwan, where the cultural revolution did not hold sway. But also, one must remember that as a foreign nation, you also have a duty to respect foreign ways of doing things, and the degradation of the Chinese polity is as much to blame on mad men from Europe and America as it is on mad men within. But in the end, one must also recognise that all which arises must also fall, and the past must not be lamented once it is gone, for that only hinders the development of harmony in the present - though one may use the past as a guide in doing that, and as a reference for revealing what tried methods worked best, and which did not.
The highest ideal, of course, is a monarch who rules in accordance with the Dharma. A monarch who is not anointed by God, but by knowledge of what is wholesome, and what is unwholesome, and conquers the world with the world's consent, and rules them with the five precepts. Not because they are overwhelmed, but simply because he IS the Noble Wheel-Turning Monarch, and the wheel treasure shows it to be so. Cakkavatti-Sihanada Sutta:
"'But what, Sire, is the duty of a noble wheel-turning monarch?'
'It is this, my son: Yourself depending on the Dhamma, honoring it, revering it, cherishing it, doing homage to it, and venerating it, having the Dhamma as your badge and banner, acknowledging the Dhamma as your master, you should establish righteous guard, ward, and protection for your own household, your troops, your khattiyas and vassals, for brahmins and householders, town and country folk, ascetics and brahmins, for beasts and birds. Let no crime prevail in your kingdom, and to those who are in need, give wealth. And whatever ascetics and brahmins in your kingdom have renounced the life of sensual infatuation and are devoted to forbearance and gentleness, each one taming himself, each one calming himself, and each one striving for the end of craving, from time to time you should approach them and ask:
"What, venerable sirs, is wholesome and what is unwholesome, what is blameworthy and what is blameless, what is to be followed and what is not to be followed? What action will in the long run lead to harm and sorrow, and what to welfare and happiness?"
Having listened to them, you should avoid what is unwholesome and do what is wholesome. That, my son, is the duty of a noble wheel-turning monarch.'
"'Yes, Sire,' said the king, and he performed the duties of a noble wheel-turning monarch. And as he did so, on the uposatha day of the fifteenth, when he had washed his head and gone up to the verandah on top of his palace for the uposatha day, the sacred wheel-treasure appeared to him, thousand-spoked, complete with rim, hub, and all accessories. Then the king thought:
'I have heard that when a duly anointed khattiya king sees such a wheel on the uposatha day of the fifteenth, he will become a wheel-turning monarch. May I become such a monarch?'
"Then, rising from his seat, covering one shoulder with his robe, the king took a gold vessel in his left hand, sprinkled the wheel with his right hand, and said:
'May the noble wheel-treasure turn, may the noble wheel-treasure conquer!'
The wheel turned to the east, and the king followed it with his fourfold army. And in whatever country the wheel stopped, the king took up residence with his fourfold army. And those who opposed him in the eastern region came and said:
'Come, Your Majesty, welcome. We are yours, Your Majesty. Rule us, Your Majesty.'
And the king said:
'Do not take life. Do not take what is not given. Do not commit sexual misconduct. Do not tell lies. Do not drink intoxicating drinks. Enjoy your possessions as before.'
And those who had opposed him in the eastern region became his subjects.
"Then the wheel turned south, west, and north. ... Then the wheel-treasure, having conquered the lands from sea to sea, returned to the royal capital and stopped before the king's palace as he was trying a case, as if to adorn the royal palace."