With so many people professing themselves king of this or lord of that, you can bet some crowns will be popping up here and there. And guess what? You are right. Every crown worn by the vying rulers of the Seven Kingdoms is detailed at some point, so it's a safe bet that we're meant to pay attention to this fancy headwear imagery.
And what's a crown without a throne to sit upon? Ah, but there is only one throne in the Seven Kingdoms, and that's the Iron Throne.
All that Glitters is Not Gold
The key to unlocking the symbol of crowns is provided by our dear Tyrion. As he proposes to Cersei, "Crowns do queer things to the heads beneath them" (4.Tyrion.61). In this case, queer means "unusual or odd" and not some of its more modern definitions. Unfortunately, "things" is a bit vague, so Tyrion doesn't quite provide us the full answer. And if we can't copy off his paper, well, we suppose we'll have to find the answer for ourselves.
To do that, let's consider the various crowns and those who sport them:
- Robb Stark's crown is "an open circlet of hammered bronze incised with the runes of the First Men, surmounted by nine black iron spikes wrought in the shape of longswords" (8.Catelyn.2).
- Renly dons a crown of "soft gold" shaped as "a ring of roses exquisitely wrought; at the front lifted a stag's head of dark green jade, adorned with golden eyes and golden antlers" (23.Catelyn.47).
- Stannis wears a "crown of red gold with points fashioned in the shape of flames" (32.Catelyn.13).
- Theon sports one that is "a band of cold iron slim as a finger, set with heavy chunks of black diamonds and nuggets of gold." Yeah, even Theon sees it as "misshapen and ugly" (57.Theon.10).
- Dany is given "a crown wrought in the shape of a three-headed dragon; the coils were yellow gold, the wings silver, the heads carved from jade, ivory, and onyx" (41.Daenerys.20)
As you might have noticed, each crown is shaped to represent the personality of the one who wears it.
Renly's crown is made of "soft gold" and adorned with roses. Similarly, Renly is a soft man by Westeros standards. Cressen remembers him as a boy enjoying "bright colors and rich fabrics" (1.Prologue.68), and as a man, Renly remains a dapper fellow who has never seen actual combat. He still enjoys color, as evidenced by his Rainbow Guard, and also festivity. For crying out loud, he's on his way to his first war but brings the party with him, complete with tournaments and feasts. Clearly, Renly is not the warrior type, and his crown shows us as much.
Alternatively, his brother Stannis feels society has often cheated him from what is his by right. When the lords sworn to him do not back his claim to the Iron Throne, it is the last slight he will tolerate. As he tells Catelyn, "The Iron Throne is mine by rights. All those who deny that are my foes" (32.Catelyn.41). This anger is represented by the flames of his crown.
Looking at these two, it doesn't seem as though crowns actually changed these characters' personalities in any way, so what are these "queer things" Tyrion is talking about? We'd argue that while crowns did not change their personalities, they do magnify them.
Consider Theon: When we met him in A Game of Thrones, he was a jerk to be sure, but once he claims his crown, we see Theon's more despicable character traits enhance. He murders the miller's two boys, beats his bedwarmer Kyra, and then uses Rodrik's daughter, Beth, as a hostage.
Then there's the poster child of magnified personalities: Joffrey. In A Game of Thrones, Joffrey was always cruel, but he did what his mother told him to at least. Once he put on that crown, he went from cruel to complete sociopath, executing Eddard Stark despite his mother's instructions to let him "take the black" (4.Tyrion.62). Joffrey becomes Joffrey in spades once he dons his headgear.
In A Clash of Kings, Joffrey continues dominating in the Most Hated Character in Westeros contest—and when you consider the challengers, that's practically an accomplishment. He tortures Sansa endlessly, using his Kingsguard to beat her on several occasions, and at one point, he brags about firing a crossbow into a crowd of starving citizens and killing a man (33.Sansa.20). The citizens' crimes? Requesting bread.
But crowns don't just make horrible kings. Robb's crown contains longswords to symbolize his growing strength as a warrior. While we see him very little in the novel, we hear often how his warrior prowess is growing exponentially, leading him to several victories against the Lannisters.
So, in A Clash of Kings, crowns don't make the king. The king makes the crown.
Call It Heavy Metal
Onto the Iron Throne. This most uncomfortable of seats was forged by Aegon the Conqueror after he subdued the Seven Kingdoms. He had his dragon, Balerion the Black Dread, melt the swords surrendered by his enemies into the shape of a throne (source). The end result is "a tangle of nasty barbs and jagged metal teeth waiting for any fool who tried to sit too comfortably" (26.Tyrion.33). So cozy.
In A Clash of Kings, the throne symbolizes the relationship of war and power in the Seven Kingdoms. Aegon earned his power—his right to rule—by way of combat, and anyone who wishes to own that power must war for it. Joffrey sits on the Iron Throne, but it is only through Tywin's war that he keeps his kingly butt planted there. Similarly, Renly and Stannis want to claim the Iron Throne, but they must first win it through battle and bloodshed.
Note that the Iron Throne grants political power, but it's not a very comfortable power. Barbs and jagged metal teeth do not sound very relaxing to us, and late in the novel, Joffrey cuts his arm on it. As Sansa wonders how badly he injured himself, she remembers, "They say the Iron Throne can be perilous cruel to those who were not meant to sit it" (66.Sansa.50). Careful there, Sansa—Joffrey might hear you.
In short, in Westeros, it seems that power earned in violence can only be maintained with violence.