“The Lyndon Johnson folks felt that he was portrayed unfairly,” Ambassador Andrew Young, a strategist and negotiator for King during the Civil Rights Movement and the former mayor of Atlanta, told Fortune. “I don’t think so. I thought he was portrayed very well. President Johnson was risking his political career. He had entire national and international issues on his agenda. Dr. King was risking his life. He thought everyday could be his last day.”

Young says that criticism of Selma is rooted in “one big misunderstanding.” Last month, President Lyndon B. Johnson’s top assistant for domestic affairs Joseph Califano wrote in The Washington Post that LBJ was more supportive of King’s goals with the voting rights marches than the film depicted. Citing a phone conversation that King and Johnson had in January 1965, Califano wrote that Johnson encouraged King to move ahead with the marches.

Although the tape of this conversation is publicly available, DuVernay declined to portray the phone call in her film. Why? Young says that DuVernay took her inspiration from a conversation between King and Johnson that occurred at the White House nearly a month before and a week after King accepted the Nobel Peace Prize in Oslo, Norway. Young, who was present for the conversation, says the meeting was late at night and all the official staff had already gone home. That didn’t bother King, says Young, because “we understood that Johnson was operating on a political agenda.”

While Johnson was empathetic to King’s desire to get the Voting Rights Act passed, the president had just spent the prior year pushing the Civil Rights Act through Congress and he felt he couldn’t turn to another issue just yet. King was adamant that LBJ press the issue immediately, and he couldn’t wait for Johnson to give his full support.

“Johnson kept saying, ‘I don’t have the power to bring this up right now.'” says Young. “There was nothing hostile in the conversation. We had no political differences with him. It was just a difference of timing. But that was a significant difference.”

It took Johnson’s administration about a month for the president’s “political agenda” to align with King’s “spiritual agenda,” says Young. At that point, Johnson became an essential ally in getting the final Voting Rights Act passed. In fact, Young says that King’s team often says that they could not have gotten the Civil Rights Act or the Voting Rights Act passed if John F. Kennedy Jr. were still in office. “He didn’t have the credential in the South, the power in the Senate, or the legislative skills to get anything through the Senate,” says Young.

Before DuVernay signed on to direct Selma, Young was brought in to read scripts commissioned by other directors interested in the role. They were all “obscene, disgusting, and inaccurate,” says Young, adding that he would have “picketed the sets” if any of them were given a green light. DuVernay, by contrast, had a command on the period and on the race relations that led to what Young deems astonishingly accurate portrayals of King, the reverend’s wife Coretta, and Young himself, among others.

“She had every aspect of that script at her command and the film should not have been interpreted as conflict,” says Young. “It should have been interpreted as everyone doing their part, and everyone doing it to the best of their ability. That’s the reason why Selma worked.”

Young added that he was disappointed that DuVernay was not nominated for a Best Director Academy Award and that the actors who played King and Coretta King did not receive nominations as well. To him, Selma proves that you don’t have to spend $100 million to make a blockbuster hit.

“Hollywood should have understood that when you’re talking about the real world and real life and real people, you can make a film that can be a box office hit with $20 million.” says Young. “Ava DuVernay did that.”

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