Since he coasted to the 100-meter finish line in world-record time at the Bird's Nest eight years ago, Usain Bolt has been the smiling face of track and field. He has served as the anchorman of the Olympics - virtually the only reason any casual fan would pay attention to a sport that has orchestrated its own slow, sad, drug-infused downfall.
His tender hamstring improving, Bolt will be back for a final go-round at Olympic glory when track starts in Rio de Janeiro on Aug. 12. If, as expected, the Jamaican wins all three sprint events - the 100, 200 and 4x100 relay - he'll only add to his legacy and cement himself at the fore of any conversation about Greatest Olympian Ever. He already is the first person to win back-to-back Olympic gold at 100 and 200 meters.
Whether viewed over the six days he runs in Rio, or over the eight years he's graced the world with his once-in-a-lifetime mix of speed, smiles and showmanship, the World's Fastest Man has offered track a reprieve from the wasteland of corrupt countries, reshuffled medals and win-at-any-cost malfeasance it has become.
Russians will be absent from this year's Olympic track meet - banned by the sport's governing body, the IAAF, which contributed to the problems as much as solved them over the years. Even with those 67 athletes out of the mix, the 10-day meet is bound to be filled with suspicious glances among the 2,000-plus runners, throwers and jumpers who will be present - all wondering if they'll get a fair shot in a sport that once defined the Olympics but now is hurting because its leaders have proven themselves either unwilling or unable to stop all the cheating.
''It breaks my heart,'' said John Carlos, the 1968 bronze medalist, whose glove-fisted Black Power salute in Mexico City created one of the games' seminal moments. ''It's a hurting thing to see your peers, their names being erased out of the record books because individuals ran faster times that might be enhanced by substances. And the powers that be might turn their heads, because they had people coming through the turnstiles with fists full of dollars.''
Money is always a good place to start when seeking the seeds of the destruction of almost any enterprise.
But the Olympics have also long been a place for countries and political movements to make bold statements. During the Cold War, the motivation was obvious: Winners and losers at 100 meters certainly didn't decide the arms race, but the Olympic medal count was the sort of scoreboard-driven result either side could use to claim superiority in the increasingly bleak standoff between East and West.
''I remember going over to the Olympics thinking, as a 20-year-old, that it's the most idealistic of institutions,'' said Tom McMillian, a member of the 1972 American basketball team that lost the gold-medal game to the USSR after officials gave the Soviets three chances to inbound the ball with 3 seconds left. ''Then, you wake up the next morning thinking, `This is a flawed institution.'''
The Soviet Union is history, but what's currently happening in Russia has been described, time and again, as `70s and `80s, Eastern Bloc-style cheating.
Two independent investigations - one into the Russian track team, the other into the country's entire sports system - have shown a pattern of top-to-bottom corruption, involving government officials, anti-doping lab workers, Olympic Committee members, coaches and, ultimately, athletes who can profit wildly from going along with the program.
Whistleblower Vitaly Stepanov, a former worker at Russia's anti-doping agency whose wife competed in the corrupted Russian system, estimated 80 percent of coaches used doping to prepare their athletes for the London Games four years ago.
''They prefer to hide everything,'' Stepanov said of Russia's modus operandi. ''They say the problem was a lot smaller than it actually was.''
Last week, the IOC rebuffed Stepanov's wife, Yulia Stepanova, the 800-meter runner who exposed Russia's doping culture after being cast out by the track program. She was seeking to compete at the Olympics, and had the blessing of the IAAF and World Anti-Doping Agency. But the IOC said no.
It was par for the course. Efforts to sanction Russia have been tinged with confusion, indecisiveness and politics.
The long-term repercussions could range from an eventual cleanup of the country's track program to a ''schism'' within the Olympic movement, as President Vladimir Putin suggested as part of the heated rhetoric that punctuated the doping-ban decisions. He called the case against Russia ''a well-planned campaign which targeted our athletes, which included double-standards and the concept of collective punishment which has nothing to do with justice or even basic legal norms.''
Russia's world-record pole vaulter, Yelena Isinbayeva, is among those staying home. She says the remaining track-and-field athletes will be competing only for ''pseudo-gold'' medals without the Russians running in Rio.
That's not so much Bolt's concern.
Over the past four years, only one man, American Justin Gatlin - the 2004 100-meter gold medalist who, himself, has served two doping bans - has been able to seriously challenge Bolt at either 100 or 200 meters. More than racing against Gatlin, though, Bolt is racing against the clock - and into history.
And yet, the doping scourge doesn't elude him, either. His relay medal from 2008 is in jeopardy now, thanks to retests conducted by the IOC that indicate teammate Nesta Carter could have used a banned substance. In the past, the IOC has stripped entire relay teams of medals even when only one person dopes.
At almost every stop he makes, Bolt is asked about doping.
In an interview before his tuneup race in London in July, he showed off the bandage covering the mark where testers had drawn their latest tube full of blood.
''Rules are rules and doping violations in track and field is getting really bad, so if you feel like you need to make a statement then thumbs up,'' Bolt said of the Russian ban.
He has never tested positive, has mostly managed to smile through the thinly veiled questions about his own doping virtue, and, when the stakes are greatest, has rarely failed to put on a show people want to watch.
The next act starts with 100-meter qualifying on Aug. 13. Bolt, who turns 30 on the day of the closing ceremony in Rio, has said he'll hang up the spikes after an encore season in 2017, but more recently has left the door slightly cracked for racing beyond that.
When he does leave, his sport will start the search for a new face - a new distraction, perhaps, from the problems that come at this sport from almost every angle.
AP Sports Writers Pat Graham and Rob Harris contributed to this report.