In To Kill a Mockingbird, what mistakes does Atticus make as a father and a lawyer?

Atticus is an excellent attorney who loves the law and
practices it with honor. He is also a responsible father who loves his children and
guides them with patience and understanding as they grow up. As a man of sound judgment
and good heart, he makes few mistakes in the novel, but Atticus is a human being and not
without error.

As a father, Atticus makes the mistake of
underestimating the depth of Bob Ewell's rage and the danger he poses to Jem and Scout.
He lets the children walk home alone after the pageant, exposing them to the attack by
the drunken Ewell. The evil of attacking children is simply beyond Atticus'
comprehension; he had never considered the
possibility.

Another mistake, perhaps, is that he does not
step in sooner to protect Jem and Scout from Aunt Alexandra's snobbish attitudes and
occasional cruelty. He acts as a mediator between Scout and her aunt, not realizing the
genuine distress Alexandra causes his daughter. When he finally understands Scout's
confusion and pain as Alexandra pressures the children to essentially change their own
identities, Atticus gives Scout permission to ignore her
aunt.

In his role as a lawyer, Atticus is a man of few, if
any mistakes. His defense of Tom Robinson is masterful and heartfelt. His neighbors in
Maycomb accept that Atticus takes Tom's case, but they are appalled that he actually
defends Tom vigorously. In retrospect, Atticus might have made a mistake in not
preparing Tom for the outcome of his trial. He could have told Tom in advance that he
most likely would be convicted, but that an appeal would follow and a conviction would
not be the end for him. He could have explained the appeals process. Had he done so, Tom
might have been more prepared for the guilty verdict and not felt so much despair in
prison that he runs blindly for the prison fence and is shot to
death.

Also, acting as Tom's lawyer, Atticus makes a
mistake in going alone to the jail at night to protect Tom. Again, he underestimates an
adversary, in this case a lynch mob. It does not occur to him that the sheriff could be
called away under false pretenses, leaving him alone and unarmed. Only Scout's innocent
conversation with Walter Cunningham's father prevents tragedy.