In Dubious Battle is not just a story of striking workers, but of Jim's development into a perfect Communist Party member and his demise. Mac is a detrimental figure for Jim, exploiting him and leading to his demise.
In In Dubious Battle, Jim, the protagonist, enters the story (And the Communist Party) as an empty shell of a man, with little or no property, family, or purpose. Jim said himself, "Everything in the past is gone." (5) He feels powerless against the forces that brought down him and his father, and wishes to find purpose in his life by attaining the power to fight these forces, and joins the Party to do so. He cites the purposeful lives he saw Party members lead in prison and their contrast to his own life, which he called a "Mess" (6), as reasons for joining the Party. Jim was very unknowledgeable about the Communist movement, and Mac was more than willing to use him as a tool for it.
At the beginning of the novel, Jim is very earnest and inquisitive in his relations, but he changes later in the novel to be more manipulative and cold. Jim treats people with the respect customary for normal relationships. He didn't try to manipulate Old Dan, and he admitted that he liked Mr. Anderson, something Mac chastised him for ("We can't waste time liking people" (86)). Later on, Jim expresses sympathy for the injured scabs, but upon Mac's response, said, "I'm not worrying about 'em." (132). This shows how Mac's Communist rhetoric is making Jim lose empathy for individuals. Later on, Jim becomes more skilled at manipulating groups of people, helping to throw out a vigilante operative.
As the story progresses, Jim becomes more and more of a hardened Communist ideologue. In a...