As Napoleon and Snowball vie for control of Animal Farm, they each use different tactics to gain more influence. Ultimately, Napoleon succeeds in driving off Snowball and gaining control. In order to destroy Snowball's legacy and permanently brand him a traitor, Napoleon accuses Snowball of several crimes including:

• destroying the windmill
• colluding with Farmer Jones
• attempting to make the animals lose at The Battle of the Cowshed
• breaking eggs
• tipping over pails of milk

Essentially, anything that goes wrong on the farm is labeled one of Snowball's attempts to overthrow Napoleon and make life on the farm miserable for the inhabitants. The more Napoleon and Squealer repeat these lies and smear Snowball's name, the more the other animals on the farm begin to doubt their own memories and rely on Napoleon and Squealer for the "truth."

In the early parts of the book, Snowball is a hero of the animals' revolution.  He is, in particular, the main hero of the Battle of the Cowshed.  But then he loses out to Napoleon in a contest to see who will rule the farm.  Napoleon chases him off the farm and starts to blame everything that goes wrong on him.  Here are some examples:

• He steals the corn
• He knocks over pails of milk
• He breaks eggs
• He tramples on the seed beds where young plants are
• He is chewing the bark off of young trees.

Basically every setback is blamed on him so that no one will blame Napoleon for them.