How does Harper Lee's To Kill a Mockingbird show whether or not people are created equal?

The question of equality is presented all throughout Harper Lee's To Kill a Mockingbird. What Lee demonstrates is that, while there is a potential for equality, there is still much to be done for that potentiality to become actuality. We are, thus, in a sense, created unequal.

In Atticus's closing remarks to the jury at Tom Robinson's trial, Atticus speaks of the belief in equality as just an ideal and reminds us that people are born differently and, therefore, not created equal in an ideal sense of the term, as we see in his following speech:

We know all men are not created equal in the sense some people would have us believe--some people are smarter than others, some people have more opportunity because they're born with it, some men make more money than others, some ladies make better cakes than others--some people are born gifted beyond the normal scope of most men. (Ch. 20)

Yet, despite these inequalities, he further argues that the US government created its court system in such a way that through the court, all men become equal. Equality is created through the court because the court system assumes innocence until proven guilty beyond a reasonable doubt. This state of assumed innocence equalizes all men, rich or poor. In addition, through the court system, all men are brought to an identical state of humility because they are reliant on the jury to decide whether or not there is enough reasonable proof to convict those brought to trial.

Yet, despite the court system being the great equalizer, ideologically speaking, Atticus further points out that even the court has its flaws because a court is no better than the men who sit on its jury, men who may believe, due to racial prejudices, that some people in our society should be treated unequally and that not all should be considered innocent until proven guilty. Due to racial prejudices, some people believe, like those sitting on Tom Robinson's jury, that people of different races are born with immoral natures and are, therefore, guilty until proven innocent.

Hence, all in all, Atticus's argument shows us that, while we are in reality born unequal, our country's legal system has the ability to be the great equalizer. Yet, the fulfillment of equality rests completely in the hands of those who uphold the law, mankind; therefore, sadly, equality remains just an ideal, not an actuality.