It’s been nearly 21 years since John F. Kennedy Jr., his wife Carolyn Bessette and her sister Lauren Bessette perished in a plane crash on July 16, 1999.

Steven M. Gillon, a historian and friend of President John F. Kennedy’s son, told People magazine on Tuesday that had he lived, the magazine publisher would have followed in his father’s footsteps successfully.

Gillon previously wrote the biography, “America’s Reluctant Prince,” which examines Kennedy’s life. Last year, he participated in the A&E documentary titled “Biography JFK Jr. -- The Final Year,” which explored the events impacting Kennedy before his death at age 38.

“John would have been president of the United States and I think the tone of our politics would have been completely different,” the professor of American history at the University of Oklahoma told the outlet.

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John F. Kennedy Jr. and his wife Carolyn, circa 1999. (Photo by Mike Segar/Reuters)

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“John would be a force for healing and bringing people together,” he continued. “John thought he could inspire people -- so I think about it often, how much better off our country would have been had John not made the foolish decision to take his plane on a hot humid July evening.”

According to the outlet, Gillon was Kennedy’s teaching assistant at Brown University, where they became fast friends. The outlet noted their friendship lasted for more than 20 years.

“John spent his whole life trying to figure out who he was and what his relationship was going to be to his father’s legacy and for most of his life, he ran away from it,” said Gillon. “And he ran away from it, because he wanted to find out who he really was, separate from the unique burden of his family.

“The other layer to the tragedy is that, by 1999, he figured out who he is,” shared Gillon. “And what he discovered is yes, he wants to go into politics. He wants to be his father’s son. But he dies just at the moment when he discovers who he is. The one thing John will always share with his father is this sense of what might have been.”

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John F. Kennedy Jr. and Carolyn Bessette. (Photo by Ron Galella/WireImage)

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Gillon said Kennedy wrestled with expectations of following in his father’s footsteps for many years.

“At first he needed to find himself,” Gillon told the outlet. “At first, he ran from his father’s legacy and he ended up running in circles. At the end of his life, he wanted to embrace his father’s legacy.”

Gillon recalled one conversation he had with Kennedy vividly.

“John said, ‘What people need is hope, realistic hope and they need to know that tomorrow is going to be better than today,’” he said. “That’s what his dad did as well as anyone since Franklin D. Roosevelt, and John understood that. John wasn’t book smart, but he had the best instincts of anyone I ever met. He could read a person, read a room -- the instincts you have to have as a politician.

“The other thing about John: You cannot discount his impact on people, what happened when he walked into a room. John inspired memories. For an older generation, he represented the unfulfilled possibilities of his father. For a younger generation, he represented a new style of leadership. I don’t think you can discount the emotional connection that John had with the American public. He understood that power. For most of his life, he tried to avoid it but if it came to the point where he was running for office, he knew how to use it.”

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John F. Kennedy Jr. exploring his father's desk. (Getty)

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According to the outlet, Kennedy was considering running for New York governor. Friends insisted that shortly before his death, Kennedy was already talking to people about pursuing that dream and planning a career in politics. Kennedy even told one pal he was ready “to go home,” referring to the White House.

“The John who would have been elected president would have been different than the John that founded George magazine,” said Gillon. “I’m perfectly aware of his limitations. John wasn’t ready at the age of 38 to be president, and he wouldn’t have been at 42, the age his father was elected. But he would have been if he had continued the same process that he had shown over the past 15 years of his life.”

Gillon admitted he still wondered what might have been for his friend.

“With John’s death came the end of Camelot,” he said. “A lot of the family mystique revolved around his father, the emotional connection that the public had to John’s father. John was his father’s son. John was the only one who could have carried his family legacy into the future. All the expectations for that were placed on him. John’s father is frozen in time and now John is too. We can’t see how he would have evolved.”

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John F. Kennedy Jr. and his wife Carolyn Bessette stop for photographers after Kennedy presented actor Robert De Niro with the Municipal Art Society of New York's Jacqueline Kennedy Onassis Medal at a gala dinner in New York, March 4. De Niro was honored for his outstanding contribution to the preservation of New York City's neighborhoods. (Reuters)

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“John had the potential to unite a nation that has become so divided,” said Gillon. “It would have been a huge undertaking and a reasonable person would say no one person could have done that, even someone whose name was John F. Kennedy Jr. But those of us who knew him think that he could have made a difference.”

Back in 2019, Gillon told Fox News Kennedy was eager to make a difference for everyday Americans.

“About a year or so before he died, we were having dinner after we had played a game of racquetball,” said Gillon. “And it was during the winter. He had spent the afternoon working with underprivileged youth in Harlem on a skating rink, and he was describing how they just clung to him as he’s skating around. And he said to me, ‘Stevie, what these kids need is hope. They need to know that tomorrow is going to be better than today.’ He paused and said, ‘I can do that. I can give them that hope.’

“And it was at that moment… John, who had kept politics at a distance, realized that it was in his DNA. He understood that he had something he could offer people. And I think from that point forward, it was just a matter of looking for the right opportunity.”