driven underground. The Capitol has been keeping its existence a secret to use it as an example to other districts.  Another example of perception versus reality is Peeta’s supposed betrayal.  He has been captured, and goes on television telling Katniss that the rebels are not who she thinks they are.

Still, I can never get around the fact that District 13 was instrumental in 12’ s destruction. This doesn’t absolve me of blame — there’s plenty of blame to go around. (ch 1, p. 6)

Throughout the series, Katniss has been torn between Peeta and Gale.  In this book, she has an even bigger problem.  Peeta’s capture by the Capitol puts her in a difficult position. She negotiates for immunity for him. 

Dead silence. I feel Gale’s body tense. I guess I should have told him before, but I wasn’t sure how he’d respond. Not when it involved Peeta. (ch 3, p. 40)

When he returns wanting nothing but to kill her, and not knowing whether his memories are really his, she feels sorry for him.  She is also being driven away from Gale by some of the choices he is making.  Gale asks her if she thinks he is heartless.  She is concerned that the weapons he is making are war crimes.

“But that kind of thinking . . . you could turn it into an argument for killing anyone at any time. You could justify sending kids into the Hunger Games to prevent the districts from getting out of line,” I say. (ch 16, p. 222)

This is the beginning of the rift between Katniss and Gale, as she realizes he has gone down a moral path she cannot follow. 

Sometimes our life is not our own, and we have a duty to others.  Katniss understands that Peeta is being used as a pawn to get at her.  She does not want to be the face of the rebellion, but she has taken that role since volunteering for the first hunger games and wearing the mockingjay pin.  She did not know what it meant, but she has become a symbol.

Snow cannot afford to waste Peeta’s life, especially now, while the Mockingjay causes so much havoc. He’s killed Cinna already. Destroyed my home. My family, Gale, and even Haymitch are out of his reach. Peeta’s all he has left. (ch 11, p. 151)

Katniss decides to be the face of the revolution, but not blindly follow the leader, Coin.  She is suspicious of her.  She does not like the restrictions placed on her in District 13.  She volunteers to join Coin’s army because she realizes that she has to play a role in the war, whether she likes it or not.  In the end, Katniss kills Coin and not Snow out of that same sense of duty.  She cannot allow another tyrant.

Collins, Suzanne (2010-08-24). Mockingjay (The Final Book of The Hunger Games). Scholastic Books. Kindle Edition.

One of the most powerful lessons from Mockingjay revolves around the novel's criticism of government, corruption, and power.  

"Absolute power corrupts absolutely." (Lord Acton)

Katniss feels this keenly throughout the novel as her mistrust of Coin grows.  She creates her own agenda when she decides to go after Snow inside the Capitol.  After witnessing her sister's murder outside the palace, Katniss realizes that she has been used once again.  In the ultimate irony, it is actually President Snow (the poster-child for government corruption and manipulation) who makes Katniss aware that Coin has in fact played her as an expendable pawn. 

Although Katniss takes this lesson the hard way, still reeling from the shock of Prim's death, she learns from her mistakes, and when given the chance, seizes the opportunity to assasinate Coin.  Katniss could not risk letting another ruthless politician become elected--in short, allowing another would-be 'Snow' to come to power.