Opinion: Showtime documentary shows Sugar Ray Leonard, Roberto Duran, Thomas Hearns and Marvin Hagler as true 'Kings'

If I could break down the main message of the wonderfully bold homage to boxing that is Showtime's documentary The Kings, which chronicles one of the greatest eras of boxing – really, one of the greatest eras in the history of American sports, it would be this: boxing is life, and life is boxing.

Sorry to sound like Yoda but no sport chronicles what it means to be a human being more than boxing. The highs and lows. The overcoming of pain. The victories. The work ethic that's required to achieve. The work ethic that's required beyond that to excel. The one-on-one battles, as the documentary shows, against opponents whether it's systemic racism, the perils of capitalism or moral pitfalls. Boxing is all of those things, because life is all of those things, and boxing has long been the ultimate human mirror.

It's this realization that makes The Kings so special. The documentary focuses on the battles and careers of four historic fighters: Sugar Ray Leonard, Roberto Durán, Marvin Hagler and Thomas Hearns.

But like all good docs, those four kings are symbols of a larger story. In this case, the film takes us from the end of Muhammad Ali's era in the 1970s, the time of Jimmy Carter and gas shortages, to the kings and the 1980s, centering on Ronald Reagan, and the beginning of the gigantic wealth gap between rich and poor.

In some ways, Reagan and Carter are as much stars of the documentary as the fighters.

Carter was ahead of his time, when he told the nation in 1979, and the documentary recounts: "Too many of us now tend to worship self-indulgence and consumption. Human identity is no longer defined by what one does, but by what one owns."

While the boxers would become wealthy in their own right, it's not hard to notice (in fact it's quite easy) to see how these four fighters of color were representatives of the people left behind as the rich took rocket ships to exuberance and wealth.

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"You don't know a seismic shift except in retrospect," says author and playwright Bonnie Greer in the film. "When I look back now, of course it was, it was massive. Muhammad Ali made boxing a metaphor for the struggle. But by the 80s (the metaphor was about) this whole idea of individualism. You know, every man/woman for him/herself."

This is the best part of the documentary. The chronicling of the lives of the fighters is excellent and the showing of their skill, and personal battles, is obviously vital.

But it's that larger prism that sets The Kings apart. It's as much about American history as it is boxing history. It's also about life.

"I'm not excusing the violence (of boxing)," said Greer, "but when it's done beautifully, fighting becomes a metaphor, the ring becomes sort of a symbol of the lottery of life."

You can see the trailer here. The four-part documentary series debuts on June 6 on Showtime.

Each boxer came to represent something different in the 1980s, a flimsy decade where superficiality was the core. Leonard was the Michael Jordan of his time, a superstar endorser (and brilliant businessman) but totally apolitical, a non-threat to white people. Hagler was substantive but wasn't gaudy enough at a time when showmen like Reagan reigned. Hearns was from Detroit, a city that was ignored by Reagan, and had to fight for the respect it deserved, like the fighter who symbolized it. Duran was highly respected in the sport (maybe the most respected), but in the Reagan era, people of color were demonized.

Duran's words about growing up in Panama are striking and powerful. His story is the most fascinating of the fighters and probably the least known. One of the more interesting parts of the doc is Duran discussing surviving extreme poverty growing up in Panama, while just a short distance away, Americans flourished in extreme wealth. It created a sense of bitterness towards the United States that fueled Duran in his first mega-fight against Leonard.

Despite losing in disgrace to Leonard in the second fight, Duran would remain a hero to much of Latin America, even to this day. (And in the documentary Duran is at times so funny, I was crying laughing. Not kidding. Tears rolling down my eyes.)

Where the fighters from different backgrounds and even countries came together were in the battles against each other. What they each did in their careers, and in those fights, remains some of the greatest achievements American sports has ever seen. Ever will see.

Because they were kings.