EVERYTHING WHICH IS NOT FORBIDDEN IS COMPULSORY (S.13.27)
This is one of Wart's earliest lessons about how power can be used for bad ends. In the world of the ants, there is no room for free-thinking or individualism. This statement, written in all capital letters on the wall of the ant colony, shows that there is only black and white, "done" or "not done," forbidden or required.
"I dew think our beloved Leader is wonderful, don't yew?" (S.13.65)
White's taking a page out of the communist handbook here. Not only does this line, spoken by an ant, reflect the Stalin-esque communism of Soviet Russia, but it also should be ringing some bells in relation to the Dear Leader, Kim Jong-un of North Korea.
They [the Norman "slaves"] knew that Sir Ector was proud of them. They were more valuable to him than his cattle even, and, as he valued his cattle more than anything else except his children, this was saying a good deal. He walked and worked among his villagers, thought of their welfare, and could tell the good workers from the bad. He was the eternal farmer, in fact—one of those people who seem to be employing labour at so many shillings a week, but who are actually paying half as much again in voluntary overtime, providing a cottage free, and possibly making an extra present of milk and eggs and home-brewed beer into the bargain. (S.14.2)
Sir Ector is one example in the book of someone in authority exercising power properly. He's not a harsh dictator and does not lord it over his serfs (even though in the social scheme of things he would have every right to). He gets right down in the dirt with them and helps them out, and treats them fairly.
In other parts of Gramarye, of course, there did exist wicked and despotic masters—feudal gangsters whom it was to be King Arthur's destiny to chasten—but the evil was in the bad people who abused it, not in the feudal system. (S.14.3)
These other masters are juxtaposed with Sir Ector, the benevolent feudal master. So, it's not the feudal system itself that's bad—it's the way the individual masters use their power for good or for tyranny. Arthur makes it his life's goal to figure out how to channel the use of Might for good.
"Only fools want to be great." (S.20.19)
With greatness comes great responsibility, Merlyn is implying to Wart. Those in positions of power either run themselves ragged by trying to do the right thing all the time (which Arthur ends up doing), or they turn tyrannous and end up like the many bad and bloody barons the King has to whip into shape.
It was the unfairness of the rape of their Cornish grandmother which was hurting Gareth—the picture of weak and innocent people victimized by a resistless tyranny—the old tyranny of the Gall—which was felt like a personal wrong by every crofter of the Islands. (Q.1.57)
Here, White links the sexual power brutally and unjustly used against Igraine to the political power brutally and unjustly used against the Gaelic people by the Gallic people (the ancient ethnic feud that the text returns to many times). It's kind of a conventional trope to describe the conquest of a nation or people in terms of the rape of a woman.
"Pulling swords out of stones is not a legal proof of paternity, I admit, but the kings of the Old Ones are not fighting you about that. They have rebelled, although you are their feudal sovereign, simply because the throne is insecure. England's difficulty, we used to say, is Ireland's opportunity. This is their chance to pay off racial scores, and to have some blood-letting as sport, and to make a bit of money in ransoms." (Q.2.72)
Where's Maury Povich when you need him to certify a paternity test? (King Uther Pendragon, you are the father.) On a more serious note, the Gaelic Federation is using pretty much any excuse it can to justify its rebellion against Arthur. They are insecure because of the old racial feud that exists between the Northern and Southern peoples.
The armies were packs of hounds, as it were, whose struggle with each other was to be commanded by Masters of Hounds, who took the matter as an exciting gamble. If the hounds had turned mutinous, for instance, Lot and his allies would have been ready to ride with Arthur's knight, in quelling what they would have considered a real rebellion. (Q.12.4)
Check out this fitting extended metaphor on the makeup of the two armies. The knights on each side have more in common with each other than they do with the serfs on their sides. They're like the Masters of Hounds, who will quickly and violently put their hounds in their places if they step out of line and disobey. So the poor serfs are the real losers here, and are totally dispensable… at least to Lot's knights.
To these young people, a sight of Arthur as he hunted in the greenwood was like seeing the idea of Royalty. They saw no man at all but England. (K.25.2)
By this point, Arthur is power personified to his people. He has ceased to be an individual guy named Arthur, and is just the embodiment of England walking around. No pressure, right?
At last he had sought to make a map of force, as it were, to bind it down by laws. He had tried to codify the evil uses of might by individuals, so that he might set bounds to them by the impersonal justice of the state. [...] And then, even as the might of the individual seemed to have been curbed, the Principle of Might had sprung up behind him in another shape—in the shape of collective might, of banded ferocity, of numerous armies insusceptible to individual laws. (C.14.3)
On the eve of Arthur's final battle with Mordred, he considers all the theorizing and philosophizing he's done regarding Might and Right, and the steps he's taken to try to curb the illicit use of force. Even making a system of laws (which Arthur thought would be the best way to take care of this problem) didn't work. In the end, force wins out.