Left: Gregory Peck is shown as Atticus Finch in the 1962 movie "To Kill a Mockingbird." (AP) Right: Jeff Daniels in "To Kill a Mockingbird" on Broadway. (Julieta Cervantes)

When the adaptation of Harper Lee’s beloved novel “To Kill a Mockingbird” premieres on Broadway on Thursday, everyone will be comparing the play with the Pulitzer Prize-winning novel and the classic movie starring Gregory Peck in his Oscar-winning turn as Atticus Finch.

Some of the biggest names in show business are involved in the production, including screenwriter Aaron Sorkin and actor Jeff Daniels as Atticus. The play has seen legal challenges from Lee’s estate, which says the script deviates too far from “the spirit of the novel.”

Though the adapted screenplay by Horton Foote, who won an Oscar for his work on the 1962 film, is generally considered to be a close adaptation of the book, the movie also departed from the novel in significant ways. Those differences involved artistic choices, but also political ones. Understanding them is critical to any assessment of the Broadway version and what it might have to say about decency and tolerance in America today.

In many ways it was remarkable that “To Kill a Mockingbird” was ever made into a movie. The story involves little dramatic action, no love interest and no female lead. Much of the book focuses on children, who are notoriously hard to cast and have little star power, and at the heart of it is a trial for a black man wrongfully accused in the rape of a white woman in Alabama, which in the early 1960s could have well invited boycotts from defensive white Southerners.

Crucial to selling the novel to a movie producer was amplifying the heroic figure of Atticus. In the novel, Atticus is a supporting character in the story of the moral awakening of the children — Scout, Jem and Dill. In the movie, Atticus is the valiant central figure. Any producer hoping to arrange financing for the film would have had to cast one of Hollywood’s leading men in the role. Lee thought that Spencer Tracy would be perfect as Atticus, and she sent him a copy of the book and a polite note asking him to consider it. But Tracy was already signed up for another film, and the role went to Peck.

In his adaptation, Foote sought ways to dramatize Atticus’s internal life. He wrote new scenes that do not appear in the book, like when Judge Taylor asks Atticus to take Tom Robinson’s case, or when Atticus overhears Scout asking Jem whether their mother was pretty.

One of the scenes that Foote rewrote at the request of the filmmakers involved Atticus’s summation to the jury. Foote included with the rewrites a contextual note that gives insight into issues the filmmakers debated in presenting the character of Atticus. Foote warned that they should not turn Atticus into “a ‘noble man’” who explains the facts to a group of “ignorant, unenlightened dirt farmers,” but rather someone who “shared their prejudices, struggled with them, and who is determined to be free of them at all costs.”

The thought may have been rooted less in Lee’s original work than in Foote’s personal history. A native of the small town of Wharton, Tex., Foote might have been thinking of his own father and grandfather, both of whom had briefly joined the Klan only to later renounce their membership.

Not much of Foote’s warning showed up in Peck’s portrayal of Atticus. His Atticus is nothing if not a “noble man.” It is the one that remains to this day an icon of American popular culture, and a touchstone of decency in American life, even after the 2015 publication of “Go Set A Watchman,” Lee’s apprentice work, which included a much more conflicted image of the character.

Yet given the times in which the book and the movie appeared, perhaps the noble Atticus wasn’t such a bad thing. In the late 1950s and early 1960s, when the South faced its biggest crisis since the Civil War, noble men were in short supply. Politicians who only a few years prior had been dismissed as jokes or nobodies stoked racist reaction to win the highest offices in the land. Otherwise decent white Southerners, who in earlier eras had sometimes stood up to the demagogues (Harper Lee’s father himself fit this description), stood by in silence.

Just weeks before “To Kill a Mockingbird” premiered in movie theaters across the country, George Wallace, an economic progressive turned reactionary race baiter, took office in Alabama, delivering his infamous inaugural address, written by a former Klansman, in which he pledged “segregation today . . . segregation tomorrow . . . segregation forever.”

In that same speech, Wallace called on “the great Anglo-Saxon Southland” to “rise to the call of freedom-loving blood that is in us.” But he also reached out to Southerners who had left the region, as well as the “sons and daughters” of New England, the Midwest, and the West. “For you are of the Southern spirit . . . and the Southern philosophy,” he said, by which he meant that they were white, and he believed that they too resented the changes that the civil rights movement demanded.

This is essential context for appreciating what Lee, Foote and Peck were trying to do. In portraying a decent man doing the right thing in a time of crisis, they were trying not to leave it to George Wallace and his ilk to define the “Southern spirit” and the “Southern philosophy.”

The spirit and philosophy of racial reaction is alive and well in American politics today in ways not seen since Wallace’s era. That fact makes the new Broadway adaptation of “To Kill a Mockingbird” more timely than it might have been just a few years ago.

Even so, Sorkin has the difficult task of pleasing throngs of Lee devotees while also making the story relevant to contemporary audiences. Can Sorkin avoid writing another white savior narrative? Can he acknowledge the agency of Calpurnia and Tom Robinson, the African American characters in the story? If he muddies the character of Atticus too much, will he run afoul of Lee’s estate, inviting further legal action? And how does he present the racism that was pervasive in the 1930s South to a new generation of Americans accustomed to trigger warnings and safe spaces?

Given the challenges, Sorkin and crew would do well to recall the definition of courage that Atticus gave to his son Jem: “It’s when you know you are licked before you begin but you begin anyway and you see it through no matter what. You rarely win, but sometimes you do.”

Joseph Crespino is professor of American history at Emory University and author of “Atticus Finch: The Biography — Harper Lee, Her Father, and the Making of an American Icon."

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