We are first introduced to Snowball after the pigs take charge of spreading Old Major’s message on the farm. We learn, “Snowball was a more vivacious pig than Napoleon, quicker in speech and more inventive, but was not considered to have the same depth of character” (2.2). It is hard to know exactly what the narrator means by “depth of character.” If he means anything like moral character, then it becomes clear, as the story goes on, that Snowball is no more lacking than Napoleon.
After Snowball is chased off by Napoleon's vicious dogs and turned into a scapegoat, it’s easy to over-correct Napoleon’s propaganda and imagine Snowball a great and noble pig. In the early chapters, though, it is clear that Snowball has as many faults as he does strengths. Though Snowball plays an important role in the Rebellion and helps set up the Seven Commandments, he is also the one to reduce the commandments to the simplistic line “four legs good, two legs bad” (3.9). It is the very simplicity of the line that later allows the sheep to bleat it over Snowball's speeches. When the other animals protest the pigs taking all the milk for their mash, Snowball is united with Napoleon in claiming that the milk is necessary for their brainwork. In other words, though Snowball isn’t around when the pigs turn Animal Farm into a dictatorship, he goes along with the first steps before he gets elbowed out.
After Snowball leads the animals to victory at the Battle of Cowshed, a divide begins to open up between him and Napoleon. We learn that he is a much better public speaker, and that he “often won over the majority by his brilliant speeches, but Napoleon was better at canvassing support for himself in between times” (5.8). In other words, Snowball is much less of a schemer than Napoleon. Snowball may only be exciting the crowds with empty speeches, but he at least seeks out their support directly instead of acting behind the scenes.
The divide between Snowball and Napoleon becomes widest over the issue of the Windmill. Snowball is passionate in support of the project, and though he doesn’t deny that it will be a difficult business, he thinks it is vital to the future success of Animal Farm. Furthermore, Snowball supports sending “out more and more pigeons to stir up rebellion among the animals on other farms” (5.12). Snowball is the forward-thinking pig. He imagines greater technical achievements on the farm and a revolution that can spread all the way across England. By contrast, Napoleon seems most concerned with consolidating the power they have already gained.
Snowball’s success is, in a way, his undoing. When he and Napoleon both make speeches to the crowd, Snowball is much more charismatic, and as he finishes, “there was no doubt as to which way the vote would go” (5.13). Napoleon, the schemer, has to come up with a response, and the only one he has is to sic the dogs on Snowball. They chase Snowball out of the yard, and he “slipped through a hole in the hedge and was seen no more” (5.14).
After Snowball is forced out, he turns into a scapegoat. Napoleon has Squealer spread all sorts of bad rumors about Snowball, destroying his great reputation, and Snowball eventually becomes a symbol of the enemy within – leading to widespread paranoia on Animal Farm. The real Snowball, however, is never seen again after the dogs chase him away.
In the early chapters, it seems that Snowball may be a double for Lenin, the leader of the October Revolution in 1917. Yet as time goes on it becomes clear that the strongest links are to Leon Trotsky, who was second in command to Lenin during the Revolution.
Immediately after the Revolution, Trotsky was a very important person in Russia, just as Snowball is a vital personality on Animal Farm. Trotsky served as the People’s Commissar of Foreign Affairs, and played a key role in leading the relatively backward Red Army to victory in the Russian Civil War. (This is like Snowball’s role in the Battle of Cowshed.) Yet Trotsky's differences with Stalin would prove to be his undoing.
In 1922, while Lenin was on his deathbed, efforts were already being made to elbow Trotsky out of the Communist Party. Lenin, who was beginning to discover serious differences between himself and Stalin, was dismayed. After Lenin’s death, Trotsky led an opposition party that was strongly critical of Stalin. Amongst other things, Trotsky was severely critical of the hierarchical and closed nature of Stalin’s Communist Party.
At least theoretically, the biggest difference between Trotsky and Stalin was that Trotsky was in favor of attempting to spread the Communist Revolution to the rest of the world. Stalin, by contrast, developed the idea of maintaining communism in one country; he thought that they should consolidate their power where they had already gained it, within Russia. In Animal Farm, we see this cleverly paralleled in the debates over the Windmill. The windmill might be seen as a symbol for Snowball’s vast dreams for the future of Animal Farm. Whether or not it is practical, Snowball stirs up the animals with his speeches and Napoleon uses the dogs to kick him out.
The attack on Snowball is an allusion to the way that Stalin forced Trotsky out of the Communist Party in 1928. Though much of the political left gave in to Stalin and claimed to recognize the error of their ways, Trotsky stayed the course. As a result, he was forced into exile and eventually killed in Mexico in 1940 by Ramón Mercader, a member of the NKVD, Stalin's police force. (See "Symbols, Imagery, Allegory" for more details.)