Wheel Turning Monarchs are Ariyas who are kings, how do they preserve the 5 precepts?

A wheel turning monarch is an Ariya who is a king, an Ariyan King. A king must defend his nation by having an army, which inevitably results in killing. Even the Buddha said when there’s a strong king, thieves and bandits hide, but when there’s a weak king, good people hide and thieves and bandits are out and about.

Isn’t it against the first precept to not only kill, but to tell others to kill? How can an Ariyan King break that rule? or are Kings exempt from that rule because of their karma?

“Bhikkhus, even a wheel-turning monarch, a righteous king who rules by the Dhamma, does not turn the wheel without a king above him.”

When this was said, a certain bhikkhu said to the Blessed One: “But, Bhante, who is the king above a wheel-turning monarch, a righteous king who rules by the Dhamma?”

“It is the Dhamma, bhikkhu,” the Blessed One said. “Here, bhikkhu, a wheel-turning monarch, a righteous king who rules by the Dhamma, relying just on the Dhamma, honoring, respecting, and venerating the Dhamma, taking the Dhamma as his standard, banner, and authority, provides righteous protection, shelter, and guard for the people in his court. Again, a wheel-turning monarch, a righteous king who rules by the Dhamma, relying just on the Dhamma, honoring, respecting, and venerating the Dhamma, taking the Dhamma as his standard, banner, and authority, provides righteous protection, shelter, and guard for his khattiya vassals, his army, brahmins and householders, the people of town and countryside, ascetics and brahmins, and the animals and birds. Having provided such righteous protection, shelter, and guard for all these beings, that wheel-turning monarch, a righteous king who rules by the Dhamma, turns the wheel solely through the Dhamma, a wheel that cannot be turned back by any hostile human being.

https://suttacentral.net/an3.14/en/bodhi

Once upon a time, mendicants, there was a king named Daḷhanemi who was a wheel-turning monarch, a just and principled king. His dominion extended to all four sides, he achieved stability in the country, and he possessed the seven treasures. He had the following seven treasures: the wheel, the elephant, the horse, the jewel, the woman, the treasurer, and the counselor as the seventh treasure. He had over a thousand sons who were valiant and heroic, crushing the armies of his enemies. After conquering this land girt by sea, he reigned by principle, without rod or sword.

‘But sire, what are the noble duties of a wheel-turning monarch?’

‘Well then, my dear, relying only on principle—honoring, respecting, and venerating principle, having principle as your flag, banner, and authority—provide just protection and security for your court, troops, aristocrats, vassals, brahmins and householders, people of town and country, ascetics and brahmins, beasts and birds. Do not let injustice prevail in the realm. Pay money to the penniless in the realm.

https://suttacentral.net/dn26/en/sujato

Do you have a citation for this assertion?

If someone has faith in the Sadhamma and triple gem, then they are a faith follower which are considered Ariyas. For someone to rule a kingdom by the Buddha Dhamma and not have faith in the dhamma sounds contradictory.

Furthermore the DN sutta I linked says that if a new king doesn’t understand and follow the precepts then the wheel-treasure disappears, implying they’re not an Ariya.

Then a certain man approached the newly anointed aristocrat king and said, ‘Please sire, you should know that the heavenly wheel-treasure has vanished.’ At that the king was unhappy and experienced unhappiness. He went to the royal sage and said, ‘Please sire, you should know that the heavenly wheel-treasure has vanished.’

When he said this, the royal sage said to him, ‘Don’t be unhappy at the vanishing of the wheel-treasure. My dear, the wheel-treasure is not inherited from your father. Come now, my dear, implement the noble duties of a wheel-turning monarch. If you do so, it’s possible that—on a fifteenth day sabbath, having bathed your head and gone upstairs in the royal longhouse to observe the sabbath—the heavenly wheel-treasure will appear to you, with a thousand spokes, with rim and hub, complete in every detail.’

Noble duties = ariye cakkavattivatte vattāhi

And there are ascetics and brahmins in the realm who avoid intoxication and negligence, are settled in patience and gentleness, and who tame, calm, and extinguish themselves. From time to time you should go up to them and ask: “Sirs, what is skillful? What is unskillful? What is blameworthy? What is blameless? What should be cultivated? What should not be cultivated? Doing what leads to my lasting harm and suffering? Doing what leads to my lasting welfare and happiness?” Having heard them, you should reject what is unskillful and undertake and follow what is skillful.

These are the noble duties of a wheel-turning monarch.’

Yes, Your Majesty,’ replied the new king to the royal sage. And he implemented the noble duties of a wheel-turning monarch.

While he was implementing them, on a fifteenth day sabbath, he had bathed his head and gone upstairs in the royal longhouse to observe the sabbath. And the heavenly wheel-treasure appeared to him, with a thousand spokes, with rim and hub, complete in every detail. Seeing this, the king thought, ‘I have heard that when the heavenly wheel-treasure appears to a king in this way, he becomes a wheel-turning monarch. Am I then a wheel-turning monarch?’

Also before wheel turning monarchs die they become monks as well

‘Dear prince, my heavenly wheel-treasure has receded back from its place. I’ve heard that when this happens to a wheel-turning monarch, he does not have long to live. I have enjoyed human pleasures. Now it is time for me to seek heavenly pleasures. Come, dear prince, rule this land surrounded by ocean! I shall shave off my hair and beard, dress in ocher robes, and go forth from the lay life to homelessness.’

On the future wheel turning monarch

Then King Saṅkha will have the sacrificial post that had been built by King Mahāpanāda raised up. After staying there, he will give it away to ascetics and brahmins, paupers, vagrants, travelers, and beggars. Then, having shaved off his hair and beard and dressed in ocher robes, he will go forth from the lay life to homelessness in the Buddha Metteyya’s presence. Soon after going forth, living withdrawn, diligent, keen, and resolute, he will realize the supreme end of the spiritual path in this very life. He will live having achieved with his own insight the goal for which gentlemen rightly go forth from the lay life to homelessness.