As the editor of Maycomb's newspaper, Braxton Bragg Underwood serves as a neutral voice of reason in To Kill a Mockingbird. Underwood rarely leaves his office, and this is one of the reasons he is silently standing guard over Atticus and the jail on the night that the lynch mob arrives. It is also possible that, as the eyes and ears of the town, he, too, has heard the rumor that Tom Robinson will be paid an unexpected visit while Sheriff Heck Tate is on a "snipe hunt." Because most newspapermen attempt to be fair and unbiased, Underwood (named after one of the Confederacy's most reviled generals) probably hoped for a fair trial; in any case, he must have decided that Tom, at the very least, deserved his day in court.
Atticus' comment later that "Braxton... he despises Negroes, won't have one near him," illustrates even more strongly Underwood's desire for justice. His editorial following Tom's death shows no sign of his hatred of African-Americans: He is, first and foremost, a newspaperman who keeps his own personal prejudices out of the story.