Tywin has made somewhat famous the saying “any man who must say ‘I am the king’ is no true king.” Could you explain what he is supposed to mean by that. I can’t really figure it out. I know it’s Tywin and the cornerstone of his character is that he is full of shit, but I would still like to understand.

Ah, good question. 

As I understand it, it’s similar to the difference between the first face of power (the coercive authority to achieve compliance) and the second and third (agenda-setting and hegemonic ideological power) faces of power. Namely, that a strong king’s authority is so secure that they don’t need to engage in displays of coercive authority because everyone already accepts them as the true source of legitimacy. 

What he’s really talking about is Aerys. Aerys was paranoid and insecure, so he kept lashing out with displays meant to emphasize his kingship – burning people alive, having people’s tongues torn out, etc. The effect was the opposite, to make him seem like a weak, mad king who didn’t deserve to be on the Iron Throne.

Contrast Aerys to Jaehaerys I – a king so secure that he doesn’t need to make open displays of force to get what he wants. All he has to do is show up on a royal progress with all of his dragons and his force of personality and his expert administrators and people knuckle under because they already believe resistance is futile.