Snowball is meant to represent the life and character of the fallen Russian leader, Leon Trotsky. In a very parallel way, Orwell gives Snowball the very traits at which the former Soviet leader excelled.
Snowball is a military mastermind with amazing organizational skills. He compartmentalizes the entire farm into subcommittees in a "divide and conquer" sort of way for the purpose of creating an army strong enough to fight against the humans.
Like a true military leader, he earns a medal in the Battle of Cowshed, in which the animals remained in possession of the farm when Jones intended to take it back. All these military successes are possible thanks to the strategies of Snowball who, as a young boar-as he is described-, also becomes the right hand of Napoleon and Squealer.
Yet, just like Trotsky, Snowball is eventually evicted from the farm by the very people who were once his allies. As he leaves, Napoleon's absolutist leadership begins to lack the skills that Snowball brings to the table as a strategist, as the brains behind every operation, and even as a code-breaker! Hence, when all begins to fall apart he is blamed for everything. It is easier for Napoleon to use Snowball as a scapegoat than to admit that he is not as good a leader without him.
In all, we can conclude that Snowball is the smartest and most dedicated soldier for the cause of Animalism. He plans, organizes, comes up with ideas, and applies a myriad of resources to fight their cause. As a result of his talent, he is put away from the farm due to, perhaps, jealousy from Napoleon. Later, he becomes the scapegoat that is blamed for Napoleon's ruling going badly. However, he will still remain the brightest of the pigs and maybe even the most able leader they could have.
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