Law does not seem to be highly regarded by the society as it relates to all people, but they certainly seem to believe it can be used per they needs in deciding race relations in the county. There is likely no other work that points out so specifically that our courts which should be the great levelers in the land as Atticus would say, actually are not levelers, but dividers. Hopefully for us, that was a phenomenon of generations ago.
To add to the above answers, Jem seems to be the child character that has the most natural sense of justice. He sees the need to equitably apply the law, and he notes the power of evidence in a trial. Throughout the trial, he seems somewhat ignorant of the racial prejudices adults take with them into their interest of this trial. If this were to play out today, the whole town would have absolutely no interest. No courtroom would be packed today for the reasons that Maycomb's court was packed on that steaming Monday in 1935. Jem's frustration with the result demonstrated his great concern for justice and Atticus confirmed this trait in him by noting if he and 11 other boys like him listened to this trial, the verdict would have been entirely difficult.
Law does seem to begin to affect at least one of the jurors and Atticus' closing remarks regarding the role of a jury rung true. Someone took "considerable wearing down" which means the verdict wasn't unanimous from the beginning and that demonstrated progress.
To Kill a Mockingbirdis, in part, a discussion of the judicial system in the South during the 1930s. The character who most exemplifies the law is Atticus, of course. He's a creator of laws (he's a state representative) as well as a defender of laws. He understands justice and upholds the law faithfully, even to the point of being willing to turn his son into the authorities for the murder of Bob Ewell (knowing he'll be acquitted, of course). His one faltering in this position comes at the very end, with Boo Radley. In general terms, though, Atticus sees the law as something that will work and should be obeyed and upheld. Atticus represents those who believe in the law, no matter what.
Jem, on the other hand, has very little experience with the law. He is, after all, not even a teenager yet, and he neither cares for nor needs to worry about the law. It doesn't affect him until that fateful summer of the trial. Jem sees the law as just, but the upholding of the law as flawed. He sees the injustice of the trial and asks "How could they do that?" His innocent belief in the purity of the law has been tainted, and his faith in the law to uphold justice is gone. He represents those disillusioned with the law.
Scout is relatively unconcerned with the law in any form. She doesn't really understand (or care) about her father's lawmaking, and during the trial she is not fully aware of the intricacies of the whole ordeal. She is comfortable enough in a courtroom, as she and Jem have grown up watching Atticus do his "lawyering." Her one clear moment of awareness comes at the very end of the novel when she understands that upholding the law byreporting Boo's actions against Bob Ewell would be like killing a mockingbird. Scout represents those to whom the law is something extraneous and not particularly applicable to their lives.
The role of law does not seem to be all that important to the majority of the cityfolk in the novel. The citizens of Maycomb, Alabama in the 1930's are still quite racist, and therefore African-Americans rarely saw true justice during this time. We see this exemplified in Tom Robinson's trial: Atticus provides a wonderful defense in the courtroom for Tom, but the jury obviously wants to persecute Tom because he is African-American.
Scout and Jem have been raised by Atticus, who tries to teach these young kids right from wrong. This, however, leads to the kids not fully comprehending the concept of racism. Jem is outraged about the injustice.
The role of law, then, is important to Scout, Atticus, and Jem, but not nearly as much to the townspeople as evidenced by their racist attitudes and beliefs.