What was the main theme of The Chocolate War by Robert Cormier?

The main theme of "The Chocolate War" by Robert Cormier revolves around the struggle against conformity and the moral dilemmas faced by individuals in a society that values power and control. The protagonist, Jerry Renault, challenges the status quo by refusing to participate in a school fundraiser, which leads to significant personal consequences. This theme highlights the importance of personal integrity and the impact of peer pressure, illustrating how standing up for one's beliefs can lead to both courage and isolation.