Regardless of Baum's insistence that The Wizard of Oz was not a political allegory, it is possible to read many aspects of it as an allegory for the populist movement and its concerns at the end of the 19th century. For example, the Tin Woodsman's backstory can be read as an allegory for the exploitation of workers in an industrializing economy:
‘I thought I had beaten the Wicked Witch then, and I worked harder than ever; but I little knew how cruel my enemy could be. She thought of a new way to kill my love for the beautiful Munchkin maiden, and made my axe slip again, so that it cut right through my body, splitting me into two halves. Once more the tinsmith came to my help and made me a body of tin, fastening my tin arms and legs and head to it, by means of joints, so that I could move around as well as ever.[']
The Woodman explains that he turned from human to tin gradually, as the Wicked Witch hacked off various parts of his body so that they had to be replaced by a tinsmith. Eventually, he lost his heart in the process. In this story, the Wicked Witch might stand in for an abusive factory owner or manager.
At the end of the 19th century, American corporations entered a period of rapid expansion. These huge companies twisted new Constitutional protections intended for Black Americans, gaining legal protections for themselves. Meanwhile, workers at corporations had few protections. Small farmers, too, felt the strain of competition with increasingly larger plants. The attitude of corporate leaders was that human workers were expendable and needed to be pushed to their maximum efficiency to maximize profit margins. Without the constraint of any of the labor laws enacted over the next several decades, corporations did utterly dehumanizing things to their workers, pushing them to behave more like machines. The Wicked Witch punishes the Woodman for his human love for the Munchkin maiden. With each punishment, he becomes a little less human and a little more mechanical until finally, he actually is the machine corporations wanted all their workers to be.
Like the populist movement, Baum's book insists on humanity's value, its persistence in the face of adversity, and the importance of letting humans be humans. The Tin Woodman may turn into a machine, but it becomes evident over the course of the book that he never really lost his heart. It is his friendship with Dorothy and the others that helps him become a productive citizen again, eventually becoming king of the Winkies. The triumph of good over evil in the book is most clearly exemplified in the way the characters vanquish the Wicked Witch of the West. The defeat of her abominable labor practices, both with the Woodman and with the people she has enslaved, suggests that corporations fail when they dehumanize their workers.
