Cross-posted from my WordPress.
As anyone who has read pretty much any of the Oz books knows, the Tin Woodman's most valued trait is his kind heart, which he associates with emotions. Obviously emotions really come from the brain, but since they can affect the heart, the organ has come to be associated with feelings. As per Nick Chopper's own admission in The Tin Woodman of Oz, his heart is kind rather than loving, although this distinction is basically just in his own mind. Anyway, in the latest issue of The Baum Bugle, an article by Richard Tuerk points out that Nick's quest in his own book isn't driven by love or kindness, but by a sense of duty. The fact that he doesn't even think of how Nimmie Amee might feel, but simply assumes that she's still pining for him like she was years before, shows that he's not particularly using his heart in this situation. With this in mind, I thought back to how Nick comes across in other books, and whether his heart is really as effective as he seems to think.
In the very first Oz book, we find the Tin Woodman, before he receives his plush heart from the Wizard of Oz, crying because he steps on a beetle. Later, he kills a wildcat that's chasing a mouse. Obviously he's not totally opposed to violence, and often does a fair amount of fighting with his axe. In Land, L. Frank Baum states, "The Tin Woodman was usually a peaceful man, but when occasion required he could fight as fiercely as a Roman gladiator." As a general rule, however, he tends to fight against those who are oppressing others. One of his most consistent traits is that he's a supporter of the helpless. In Patchwork Girl, he absolutely refuses to allow Ojo to take the left wing of a yellow butterfly, even though he needs it (or at least thinks he does) to restore his Unc Nunkie to life. Dorothy and the Wizard has him going along with the Wizard's plan to use trickery to save Eureka from execution. In Lost Princess, we learn of a ferryman whose power to communicate with animals was taken away at Nick's command as punishment for his cruel actions against a fox, a fish, and a bird. Exactly how the Tin Man accomplished this is unclear, but as the power for humans and animals to talk to each other is usually shown as pretty much absolute within Oz, it comes across as a pretty severe penalty. One exception to this rule, perhaps, is that he laughs off Jinjur's Army of Revolt. The girls have invaded and conquered the Emerald City, but they do have some legitimate grievances. Nick advises treating Jinjur kindly, but that's about it as far as his sympathy goes. Perhaps he's more biased than he would normally be due to the fact that the girls drove out his best friend, the Scarecrow. Also, as in Tin Woodman, he shows some signs of unwitting sexism.
Another consistent characteristic of the Tin Emperor is his pride, pertaining largely to his appearance. The Scarecrow points out in Land that his "friend was ever inclined to be a dandy," and we learn that he's taken the title of Emperor despite the fact that the Winkie Country is only a kingdom. (Actually, later books reveal that it contains other smaller kingdoms, so "Emperor" isn't really that far off, but it's true that none of the other quadrant rulers use it, nor does Ozma.) When Ruth Plumly Thompson, who used the Scarecrow and Cowardly Lion quite frequently but tended to relegate the Tin Woodman to bit parts, finally gave Nick a major role in Ozoplaning, it's his pride that she showcases. I'm not the only one to think Nick seemed a little off in that book, but as Kenneth Shepherd observed, his claiming Stratovania for Ozma fits pretty well with his insistence on being called an emperor. It sort of fits that the Tin Woodman's sense of pride and honor would occasionally get in the way of his kindness. He's a quite sympathetic individual, sure, but he's not at all humble.