Could Animal Farm still be an effective tale if it were not an allegory that describes how the animals lost their liberties for which they have fought?
Animal Farm is not just an allegory about losing liberties. In fact, Animal Farm offers a stark warning to its readers about the dangers of absolute power and totalitarian regimes. Orwell demonstrates this message through his characterization of the pig, Napoleon.
When the animals take control of the farm, in Chapter Two, Napoleon works in conjunction with the other pigs. Together they develop the principles of Animalism and plan the day-to-day running of the farm. But, over a brief period, Napoleon emerges as a single leader, determined to pursue his own agenda at the expense of the other animals. We see the first glimpse of this at the end of Chapter Two when Napoleon steals the milk to put in the pigs' mash. Later, through Squealer, Napoleon appeals to science to justify this selfish act by arguing that the pigs need milk and apples because it is good for their bodies and minds.
As the story develops, Napoleon's power grows and the animals are defenseless against him. This is because he has trained the puppies to act as his personal bodyguards. He runs Snowball off the farm, for example, and sells Boxer to a glue manufacturer.
It is in the closing chapter of the book, however, that Orwell's message about absolute power is at its strongest. The seven commandments have been replaced by one single message: that all animals are equal but some are more equal than others. Furthermore, Napoleon is wearing clothes, walking on two legs and drinking whiskey in the farmhouse. He has become the living embodiment of all that the animals rebelled against and life is now far worse for them than it ever was under Mr Jones.