In "To Kill A Mockingbird," what do the columns on the building symbolize?

Most courthouses have a distinct architecture which embodies the ideals of truth and justice.

In To Kill A Mockingbird, Harper Lee describes the columns in such a way they transcend time. Columns are a fundamental structure in ancient Greek and Roman architecture. Over time this architecture came to represent what American freedom "looked" like. It is no accident the Capitol and Supreme Court look the way they do.

The Lincoln Memorial's columns are a distinguishing part of the structure. The thirty-six columns represent the number of states in the union at the time of Lincoln's death. In 1939, Marian Anderson an African American woman sang "My Country, 'Tis of Thee" on the steps of the Lincoln Memorial because no other Washington venue would allow her to. In 1963 Dr. Martin Luther King Jr. had a dream, it was delievered on the steps of the Lincoln Memorial.The columns are filled with "humanity". Lincoln was referred to as "The Great Emancipator", the same could be said of Atticus Finch's defense of Tom Robinson.   

The columns of the courthouse are symbolic because they do not represent truth and justice. To represent truth and justice, the columns require humanity. Atticus Finch's defense of Tom Robinson represents that humanity. Prior to the Civil War the columns were just columns. Without humanity for our fellow man, columns just hold up the roof.