
The most important theme is definitely government overreach, most often in the form of lying, or rather bending the truth, and then force-feeding their lies to the citizens. In the first book, the citizens of the Capitol willingly watch the bloodbath of the Hunger Games every year, and they celebrate it like a month long Super Bowl because they're told from childhood that's entertaining. Thus, in the first book, the Capitol citizens are the victims of the government lying while the Districts are enslaved and are fully aware of it (although this seems less apparent with the career tribute districts). The second book is about the government crushing out the sparks of rebellion, so more than the last book the common people are being lied to and told nothing will change, that everything must stay the way it is. In the final book, it goes to a much more personal level, down to specifically Katniss and Peeta. Peeta got brainwashed by the Capitol to believe one of the only friends he had in Panem was a dangerous and he had to kill her, or else bad things would happen. Do as the government says or else bad things will happen. Katniss, on the other hand, is seeing through the rebel movement - how they were bending the truth so as to morally justify their actions, and to prevent what would essentially be a reverse Panem with the citizens of the districts enslaving the Capitol, she takes the drastic step of killing Coin.