What do we find out about Mr. Underwood in To Kill a Mockingbird?
Mr. Underwood is the editor of the local rag, The Maycomb Tribune. A fairly insignificant man, he pretty much epitomizes the Average Joe in this small Southern town. A virulent racist and white supremacist, like just about everyone else in Maycomb, he nonetheless realizes that a grotesque miscarriage of justice has taken place with the conviction of Tom Robinson.
What Underwood lacks in racial sensitivity he partially makes up for in terms of empathy. Despite his racism, Underwood can see beyond Tom's race just long enough for him to realize that the man is one of life's mockingbirds, and as such, he should not be harmed. It's interesting that his empathy in this regard is similar to that of his good friend, Atticus Finch, despite their radically different outlooks on race.
This would appear to suggest that it's just as wrong to take a white racist at face value as it is to make a judgement about an African-American male charged with raping a white woman. In both cases, there's a lot more going on than meets the eye. It would be far too easy to write off Mr. Underwood as just another one-dimensional white Southern racist. But thanks to his relationship to Atticus, we can see that that's not the case, and that though he's one of the book's minor characters, his added dimensions make him no less interesting for that.