Themes: A Clash of Kings
In A Clash of Kings, many characters appear to be men and women of honor, at least on the surface. For some, it is no different than putting on a ring or necklace; you put it on when you want to look your best, but take it off when you need to get down to practical matters.
For others, honor is a way of life; they steadfastly adhere to a code of honor even when going down the easy (and dishonorable) path would prove to be more advantageous or beneficial. In the book, there is a story arc where a youth who has taken over Winterfell with a surprise attack in the middle of the night then finds himself face-to-face with a thousand-strong northern host, led by the castellan of Winterfell, just come back from stopping ironmen raids on the western shore. The castellan calls for a parley with the youth, and though the youth's handful of men warn him not to do so for they feel the castellan and the northern men will kill him while he rides out to treat with them, the youth does so anyway. He knows that, although the castellan and the northern host would like nothing better than to see him dead, the castellan is a knight, renowned for his sense of honor and justice. And though they trade insults and threats, the castellan and the rest of the knights allow the youth to ride back to the castle which he has taken hostage as per the rules of a parley.
A lot of the characters in A Clash of Kings find the concept of honor impractical and detrimental to ambition. To them, honor might win you the loyalty of your men or the admiration of the common folk, but it will prove useless when it comes to seizing power. In order to seize power, they believe that one must employ the practical, even the underhanded. And they believe that even those who are noted for their honor will surely give in to their base instincts and desires - the question is when. When Sansa Stark tells the Queen that the knights of an attacking army would surely never rape or harm the women and children in the city should they score a victory, Cersei Lannister, a creature of naked ambition, is amused at the girl's naivety.
Family is a very important concept in A Clash of Kings; loyalty to one’s family is what keeps the Seven Kingdoms together. Each noble house constitutes one family; for example, anyone with the last name Stark would belong to House Stark. Smaller Houses serve and pledge fealty to these Great Houses, and all Houses, Great or small, ultimately pledge fealty to the King of the Iron Throne.
During the course of the story, even devious or morally-corrupt characters display strong loyalty to their families. In a way, this is not unexpected, as there is an incentive for being loyal. The Seven Kingdoms is a feudal society; therefore, being born into a noble family means enjoying all the privileges and power associated with one’s family. By protecting the family, one is also protecting one’s claim to that privilege and power. It is the rare man or woman who spurns the gifts they were born into - many will do absolutely everything they can to maintain the power (perceived or otherwise) of their House.
An insightful example of the importance of family would be the case of the Lannisters. Although they come across as power-hungry, ambitious and morally ambigious to the other Houses (and to the reader), they will not let a slight against their family go unpunished. In A Game of Thrones, Jaime Lannister, on learning that Eddard Stark's wife managed to capture his brother Tyrion, dared to confront and attack the Lord of House Stark on the streets of King's Landing, in open sight. He becomes so driven by the desire to rescue his brother that he even leaves the capital despite being a sworn member of King Robert Baratheon's Kingsguard. He also starts a war over it. These chain of events acts as the precursor for the civil war that takes place in A Clash of Kings. And as chance would have it, Jaime Lannister himself is eventually captured by Robb Stark's forces. Now, having escaped from Catelyn Stark's clutches, it is Tyrion's turn to rescue his brother from imprisonment. And he will do anything to achieve that end - even if it means doing something underhanded and dishonorable.
Another example of family matters coming before all else is House Tully. Their family words are: Family, Duty, Honor. To the Tullys, the arrangement of these three words is a matter of great import: duty and honor are important, but family has to come first.
Sex and Gender Roles
A Clash of Kings largely takes place in a medieval setting, where men rule and hold power. The eldest son always inherits the title and lands of his father; if he should meet an untimely end, the next eldest son claims the inheritance. Women can hold no land or castle; the role they play is limited to one of taking care of their husband’s family and estate.
There are some women who struggle with these oppressive chains; they dislike being shackled by the expectations for their sex, and so try to navigate through Westerosi society in their own special way. Some do it subtly, keeping their femininity on the surface, intact for the world to see, but who then plot and scheme behind closed doors, as power hungry as any ambitious man. Then there are those who do so in more direct and obvious ways, who strap on armor, wield sword and shield and engage their enemies on the battlefield alongside their male counterparts.
One of the main characters in the book, Cersei Lannister, laments the fact that though her twin brother Jaime and her were so much alike as children that even their father could not tell them apart, they were given vastly different things as they grew up. Jaime learned how to fight with weapons while she had been taught how to sing and smile prettily; Jaime became heir to the Lannister castle and lands, while her fate was to be married to some lordling or other for their father's political gain. The unfairness of the whole situation, plus the attitude of the Seven Kingdoms towards women in general, has led to Cersei fuming over the fact that she has been treated so differently just because she was born the "wrong" sex.
Omens and Portents
One of the themes that is explored far more in A Clash of Kings than in the previous book is that of omens and portents. These abound aplenty in the story, with the recurring theme being that they can mean different things to different people. In fact, the story in A Clash of Kings starts off with an ominous sign: a huge red comet burns in the sky, visible from every part of Martin's world.
Though everyone sees the same red comet and take it as an omen, they all come to different conclusions on just what the appearance of the red comet means. The young King Joffrey thinks the comet a sign of his coming glory, as it burns brightly across the sky on his name day. The common folk of King's Landing call it The Red Messenger, coming to the world as a herald before a king, to warn of the fire and blood that will follow. The men of the Night's Watch who have gone beyond the Wall claim that the gods sent the comet to help light their Commander's way through the Haunted Forest. Across the Narrow Sea, Daenerys Targaryen sees the red comet as the herald of her coming, a message from the gods to show her where she must go next.
Dreams and Wolf-Dreams Dreams also appear more frequently in A Clash of Kings compared to its predecessor. In A Game of Thrones, dreams were more about what some of the younger main characters wanted to be. But in A Clash of Kings, dreams are the manifestations of the character's deepest desires and emotional state of mind. In Catelyn Stark's dreams, her husband is still alive and waiting for her in bed while her son Bran is whole again. When Tyrion dreams, he dreams of his first wife Tysha, and how much she had loved him. After Theon has taken over Winterfell and butchered two innocent boys, he starts having bad dreams and horrific nightmares.
The power of dreams and their ability to show glimpses of the future feature strongly in the book, especially so with the character of Jojen Reed, who claims that his dreams are green dreams, and that they always come true. But with the dreams in the story, even with Jojen's green dreams, it is often hard to interpret just what the dreams mean, until much later. Soon after Jojen meets Bran, he tells Bran that the ocean is going to come to Winterfell and that many of the castle-folk are going to drown. Bran points out the impossibility of such a thing happening, as Winterfell is many miles away from the shoreline. But he later sees that the dream does indeed come true, just not in the way he expected.