To a country that invented the Hall of Fame and idolises sporting heroes, the names Tommie Smith and John Carlos are still pregnant with symbolism. The photograph of their proud-but-solemn "black power salute" on the podium at the Mexico Olympics in the summer of 1968 remains one of the defining images of a generation.
Yet exactly four decades after Smith and Carlos lifted gloved fists and bowed their heads in that dignified yet somehow menacing protest, their legacy has descended into a personal rivalry more bitter than anything they experienced on the athletics track.
Today, they refuse to speak. They will not appear together in public. In a long-running feud, each has written an account of 1968 that contradicts the other; each has attempted to take credit for the now-legendary protest; and each has publicly called their former comrade a liar.
As a result, the 40th anniversary of Carlos and Smith's snub to "The Star-Spangled Banner" is overshadowed by uncertainty and unlikely to be formally celebrated at this summer's Olympics in China.
A lucrative deal to make a Hollywood film about their civil rights gesture has also fallen through, because neither man could agree terms regarding how the run-up to the race and their subsequent protest ought to be portrayed.
Even an HBO documentary about Smith and Carlos that was screened in the US this week descended into low-level point-scoring about their athletic achievements. Smith, who won a gold medal in the 200 metres race, in a record time of 19.92 seconds, saw fit to claim his rival didn't deserve to have been inducted into the Athletics Hall of Fame, since he'd only won bronze. Carlos countered by saying that he'd deliberately let Smith finish ahead of him.
In separate interviews with the Los Angeles Times this week, it was revealed that they have barely spoken to each other since the early 1990s, despite living just a short drive apart in southern California. Smith described their relationship as "strained". Carlos would call his former team-mate only "Mister Smith".
The dispute has divided the civil rights movement who engineered the original protest. Harry Edwards, who was their mentor at San Jose State University – where both athletes studied and trained – and is widely seen as the real architect of the 1968 protest, compared their dysfunctional relationship to that of two elderly drunks disputing former glories.
"What you have here is two old men sitting at a bar an hour before closing ... squabbling over ever-evolving war stories," he said. "It's a great shame, because it overshadows what they did, and overshadows a gesture that was emblematic of an era in which black athletes, from Ali onwards, decided that it wasn't enough to compete like Jesse Owens had done: they wanted to revolt against injustice in American society to secure integrity, respect and a broader kind of legitimacy.
"Unfortunately, what Carlos and Smith did became so symbolic, and so iconic, that for most of the past 40 years they have been forced to reverse-engineer what happened, and to go over the individual events time after time in interviews. And naturally their memories are different. Naturally, they contradict each other, and even sometimes contradict things they themselves have said in the past."
In 1968, with the Vietnam War raging, Bobby Kennedy and Martin Luther King recently assassinated, and the battle for civil rights being joined in dozens of America's cities, the conduct of the country's black athletes was the subject of fierce controversy. Mr Edwards, a sociology lecturer, was one of the civil rights movement's most prominent figures. In the run-up to Mexico, he helped create a group called The Olympic Project for Human Rights, which sought racial equality across sport. Although it initially sought to organise a boycott of the Olympics, it eventually decided to ask its supporters to make individual gestures of protest. Although black athletes dominated the games, winning 10 gold medals and setting seven world records, only Smith and Carlos complied with the request.
The backlash was immediate and far ranging. The US Olympic Committee kicked both athletes off the team, and sent them home in disgrace (it only allowed them to retain their medals so they could count against the Russians on the final scoreboard). The media demonised them, describing a "Nazi-like salute", and comparing them to "black-skinned storm troopers". Both Smith and Carlos received death threats, and were wrongly accused of belonging to the radical Black Panther group.
In an interview immediately after the protest, Smith threw a pail of nitrate into the already volatile mix.
"I wore a black right-hand glove and Carlos wore the left-hand glove of the same pair," he said. "My raised hand stood for the power in black America. Carlos's raised left hand stood for the unity of black America. Together they formed an arch of unity and power.
"The black scarf around my neck stood for black pride. The black sock with no shoes stood for black poverty in racist America. The totality of our effort was the regaining of black dignity."
Back home, their athletic careers never recovered, and attempts to earn a living in American football were short-lived. Both Smith and Carlos later made careers in education in Los Angeles, but scars have always remained. Carlos has blamed the suicide of his first wife on the post-Olympic pressures they faced.
That, however, is nothing compared to the more recent pressure they've heaped upon each other. In interviews over the past few years, they have offered differing recollections of almost every detail of what happened in Mexico in 1968.
Smith, now 64, claims to have come up with the original idea of raising their fists, because his first wife, Denise, had the brought the black leather gloves in Mexico City. Carlos, 63, claimed the whole thing was his idea. Carlos also insisted he allowed Smith to beat him in the race. Not so said Smith, boasting that he turned on his "Tommie Jets" to secure victory.
Smith's version of events is chronicled in the autobiography, Silent Gesture, co-written with the journalist David Steel last year. Carlos, who wrote his own auto-biography in 2001, has called his rival's book "trash".
"The fact that he wrote that he gave me the glove and told me to just do what he did – it's absurd to make a statement like that," he said. "Anybody that's ever known me knows I ain't never been no follower."
Given the tone of the debate, the chances of both men burying the hatchet for a public commemoration of the 40th anniversary of their protest now look slim to the point of non-existence. But, Mr Edwards, who remains close to both, hopes that in the fullness of time their disagreements will not overshadow a historic legacy.
"You know, I actually see this as more funny than anything else," he said. "Because in 100 years' time, when people look back on Carlos and Smith, I don't think they'll see all the arguments. Instead, they'll go to San Jose State University, and they'll see that 30ft-high statue of them that stands there, and they'll realise how these two are emblematic of a historic struggle. And that's what will really matter."