What are two common themes evident in each novel: Animal Farm and 1984?

Although these novels are very different in their settings and characters, they share some common themes. The first of these is power. Specifically, in both novels, Orwell explores the idea that power has a corrupting influence on those who possess it. In Animal Farm, this is shown clearly through the pigs who take control of the farm after Mr. Jones is overthrown. Instead of building a utopia as imagined by Old Major, the pigs become increasingly corrupt and self-serving. By the end of the story, they are just as tyrannical as the humans they overthrew.
We find a similar situation in 1984 in which the Party has become so corrupted by its power that it denies its citizens their basic human rights. The Party spies on every member, uses violence as a means of control, and imprisons those who do not conform to its every rule and desire.
Secondly, betrayal is another theme which is present in both novels. In Animal Farm, it is the pigs who betray the other animals. Specifically, their corruption of the Seven Commandments leads to a betrayal of the ideals which inspired the Rebellion. Instead of making all animals equal and free, the pigs create a clear distinction between themselves and the others. They enjoy the finest quality of life while the other animals are left on the brink of starvation and worked as hard as possible.
In 1984, it is Winston who is betrayed. Firstly, he is betrayed by O'Brien because he believes that O'Brien is an ally when, in fact, he is working for the Party. Secondly, he is betrayed by Julia who chooses to save herself in Room 101 and, therefore, betrays their love.
Ultimately, as a result of power and betrayal, both Winston and the animals are trapped in a system from which there is no escape.