"John was irresistible. I don't think anybody who ever met John, whether they were a young child, a teenager, adolescent or adult, ever could resist the charm and charisma that was John's," says CBS News and CNN correspondent Christiane Amanpour.
When John married Carolyn Bessette in September 1996, people compared them to John's parents. It was supposed to be the start of a new Camelot, but author Laurence Leamer says it was quickly apparent that Carolyn was not Jackie Kennedy.
"She hated the attention," says Leamer. "From the day she came back from that honeymoon and saw this paparazzi across the street, she couldn't deal with it."
"I think she found it extremely difficult, especially in the early years, like Princess Diana," adds Amanpour. "She couldn't breathe or leave their apartment or get her hair cut without a horde of paparazzi not just taking her picture but yelling at her, 'Look this way. Do this.'"
Bessette became a political problem. Leamer says that at the end of his life, John Jr. was seriously considering going into politics. He was interested in running for the New York Senate seat, the office once held by his uncle, Bobby Kennedy.
But JFK's only son would be entering politics for the first time against a formidable opponent: former first lady Hillary Clinton.
"He had two problems," says Leamer. "Whether Hillary was going to go, and secondly, his wife, whether Carolyn would be able to take it."
John was afraid Carolyn was too fragile, so he decided not to enter the race. "Everybody looked at him as the repository of his father and his family's greatness," says Amanpour.
"He grew up with that burden but not willing to let it pull him down," says Leamer.
Leamer believes that John never got over the loss of his father.
His life "was a quest, literally, for his father, and that's why he relates to the Secret Service, and starts calling some of them Daddy -- any kind of male figure to bond with," says Leamer.
"As a young man, he wanted to do just raise hell and have a happy life. He told one of his close friends that 'that's what my father would have wanted. That's what my father would have done.'"
John's mother also encouraged her son's adventurous side in a way that seemed almost risky.
"I was sitting at my desk one evening, and I get a phone call, and the person says, 'Hello, this is Jacqueline Kennedy Onassis,'" recalls John Perry Barlow, a former lyricist for the Grateful Dead.
Barlow runs a cattle ranch in Wyoming, and Jackie wanted her son, then 17, to spend a summer on the ranch. "We had an immediate bond," says Barlow.
"She wanted her son to grow up to be a man," says Leamer. "Let him take chances. Let him learn and grow. Most mothers wouldn't have done that."
But did those early decisions by his mother help John or hurt him? "He was a cut-up in school," says Leamer. He was a lousy student. He got poor grades."
At Brown University, John spent most of his time hanging out with close friends like Chris Oberbeck. "He was a great friend, a terrific person to be around," recalls Oberbeck.
John clearly cherished his father's spirit. He spent quiet moments in his college room sitting in a special chair, the same one his father used in the Oval Office.
"He'd sit in his chair and he had this book of his father's speeches that he made in the first 100 days," says Oberbeck. "He goes, 'Can you believe all these speeches that he made? In those first 100 days?' He was just amazed."
And in true Kennedy fashion, John never met a sport he didn't like. He took up kayaking, heli-skiing, and of course, flying.
"He wasn't seeking danger as much he was seeking purity," says Leamer. "It was because he just got an incredible rush with this pure feeling."
Over the years, John sometimes gave America a glimpse of a Camelot that was still within reach.
In 1988, he delivered a rousing speech at the Democratic convention. But he never built on that moment. Instead, he returned to his Peter Pan ways until his mother's death on May 19, 1994.
Finally, at 33, he seemed to grow up before our eyes. John broke up with longtime girlfriend Darryl Hannah and created George magazine.
"I just remember feeling great for my friend," recalls Oberbeck. "He had done something really on his own and had come up with something original and pulled it off."
George initially was a great success, but it also created some uncomfortable situations for Kennedy. During the Monica Lewinsky scandal, John Jr. longed to write an editorial supporting President Clinton. But friends warned him against it.
"My husband thought it was a good idea, but he warned him," recalls Amanpour. He said, 'Look, before you go plunging there, you have to be prepared for everybody to come down on you and your father and start to bring up similar issues.'"
That's the last thing John wanted to do, give the press a reason to revisit his father's fabled womanizing. "It irritates John, but it was the truth," says Leamer. "So the whole year goes by and there's nothing in the magazine about that whole scandal."
Toward the end of his life, in the summer of 1999, the pressures on John were growing. George was losing money. He had passed up a chance to run for the Senate, and his relationship with Carolyn was growing more and more stormy.
"Sometimes she wouldn't leave her apartment for two weeks at a time," says Leamer, who admits that Carolyn took cocaine. "The idea that she was an addict is wildly exaggerated. She was part of that kind of models-design world where that is very common. She did that and she took anti-depressants, which don't go too well together."
John spent at least one night alone in a hotel, leading to gossip about their marriage. And he sought comfort where he always had: in risky behavior.
"It was an essential element of his life and had reached, what some people thought, a dangerous point in the last years of his life," says Leamer. "His sister would not go up in a plane with him. She thought it was too dangerous."
Sadly, all of us know how this story ends. But if he had lived, would he be in politics today?
"Oh, eventually, he was gonna enter politics, no question about it," says Leamer.
What happened to the Camelot myth when John Jr. died? "It ended with his death, and I think that's why Americans that week of his death were so moved by it," says Leamer. "We were deeply moved because we realized we'd lost him. We'd lost that kind of myth, that kind of promise."