"Whenever anything went wrong it became usual to attribute it to Snowball." What was Squealer's mission in Animal Farm for doing this?

As Comrade Napoleon's right hand man in George Orwell's
Animal Farm, Squealer's most valuable asset was his ability to
spread propaganda among the animals. He was very successful, and the animals rarely
questioned his words. Although Snowball was no longer on the farm, many of the animals
remembered his bravery and wisdom while he was there. There was always a chance that he
would return and divide the animals, thereby weakening Napoleon's control. By blaming
Snowball for anything negative that happened on the farm, Squealer was able to plant
the idea that Snowball was a traitor and was working against the animals and with the
humans. This message could only strengthen Napoleon's position and diminish any possible
loyalty that any of the animals still felt toward Snowball.