According to Srimad-Bhāgavatam the monarchical regime represents the Supreme Lord, the Personality of Godhead. The king is said to be the representative of the Absolute Personality of Godhead because he is trained to acquire the qualities of God to protect the living beings. The Battle of Kurukshetra was planned by the Lord to establish the real representative of the Lord, Mahārāja Yudhisthira. An ideal king thoroughly trained by culture and devotional service with the martial spirit makes a perfect king. Such a personal monarchy is far better than the so-called democracy of no training and responsibility. The thieves and rogues of modern democracy seek election by misrepresentation of votes, and the successful rogues and thieves devour the mass of population. One trained monarch is far better than hundreds of useless ministerial rogues, and it is hinted herein that by abolition of a monarchical regime like that of Mahārāja Parikshit, the mass of people become open to many attacks of the age of Kali. They are never happy in an overly advertised form of democracy.

It is clear therefore that a person who is not well versed in the Vedic injunctions (veda-Sāstra-vit) should not run for election as president, governor, etc. Formerly kings were rājarshis, which meant that although they were serving as kings, they were as good as saintly persons because they would not transgress any of the injunctions of the Vedic scriptures and would rule under the direction of great saintly persons and brāhmanas. According to this arrangement, modern presidents, governors and chief executive officers are all unworthy of their posts because they are not conversant with Vedic administrative knowledge and they do not take direction from great saintly persons and brāhmanas. Because of his disobedience to the orders of the Vedas and the brāhmanas, King Vena, Prithu Mahārāja's father, was killed by the brāhmanas. Prithu Mahārāja therefore knew very well that it behooved him to rule the planet as the servant of saintly persons and brāhmanas.

Mahārāja Yudhiṣṭhira was not a typically unenlightened political leader of modern democracy. Mahārāja Yudhiṣṭhira was instructed by Bhishmadeva and the infallible Lord also, and therefore he had full knowledge of everything in perfection.The modern elected executive head of a state is just like a puppet because he has no kingly power. Even if he is enlightened like Mahārāja Yudhishthira, he cannot do anything out of his own good will due to his constitutional position. Therefore, there are so many states over the earth quarreling because of ideological differences or other selfish motives. But a king like Mahārāja Yudhishthira had no ideology of his own. He had but to follow the instructions of the infallible Lord and the Lord's representative and the authorized agent, Bhishmadeva. It is instructed in the Shāstras that one should follow the great authority and the infallible Lord without any personal motive and manufactured ideology. Therefore, it was possible for Mahārāja Yudhishthira to rule the whole world, including the seas, because the principles were infallible and universally applicable to everyone. The conception of one world state can only be fulfilled if we can follow the infallible authority.               

An imperfect human being cannot create an ideology acceptable to everyone. Only the perfect and the infallible can create a program which is applicable at every place and can be followed by all in the world. It is the person who rules, and not the impersonal government. If the person is perfect, the government is perfect. If the person is a fool, the government is a fool's paradise. That is the law of nature. There are so many stories of imperfect kings or executive heads.               

Therefore, the executive head must be a trained person like Mahārāja Yudhishthira, and he must have the full autocratic power to rule over the world. The conception of a world state can take shape only under the regime of a perfect king like Mahārāja Yudhishthira. The world was happy in those days because there were kings like Mahārāja Yudhishthira to rule over the world.         
-Compilations from Srila Prabhupada's Teachings