Clevinger is depicted as a highly emotional character, deeply affected by his beliefs and the principles he holds dear. His passion is evident as he becomes animated during discussions, often showing signs of distress such as moist eyes and a quivering mouth. This intense emotional state reaches a peak when he finds himself struggling to breathe, highlighting the depth of his conviction and the turmoil it causes him.

Despite his strong beliefs, those around him perceive Clevinger as irrational or overly passionate, labeling him as "crazy." This reflects a broader theme in "Catch-22," where the clash between individual conviction and societal norms often leads to misunderstanding and isolation. Clevinger's fervor illustrates the conflict between idealism and the stark realities faced by individuals in a war-torn world.