What metaphors are used in Jailbird by Kurt Vonnegut?

Sacco and Vanzetti never actually appear in the novel, but they referred to several times. Like a number of other secondary characters, Sacco and Vanzetti are actual historical individuals, Italian immigrant workers who were falsely arrested, tried, and executed for murder. They are portrayed throughout the book as icons of the wronged, idealized and victimized metaphoric examples of how the less advantaged can be destroyed by capitalism.