Some Olympiads are born controversial, some achieve controversy, and some have controversy thrust upon them.
Though few editions of the modern Olympic Games have been as bitterly contested as the Beijing summer Games that open in August, these are scarcely the only ones to have sparked dispute. Indeed, those disputes – not sporting achievements – are often what make Olympic Games memorable.
"People will remember a really great athletic moment," says historian David Wallechinsky. "But, in general, it is the controversies that stick out."
A case in point: Sports fans still remember Bob Beamon's massive long jump in Mexico City in 1968, setting an Olympic record that has yet to be beaten. The rest remember the Mexico Olympics for the Black Power salute that US athletes Tommie Smith and John Carlos gave from the podium.
Some observers have likened the controversy surrounding the Beijing Games, fanned by pro-Tibet and human rights activists, to the international misgivings about the Berlin Olympics in 1936, hosted by Adolf Hitler.
In both cases, "you have persecution going on before the Games and other countries nervous about bringing teams to compete," says Kevin Wamsley, head of the International Centre for Olympic Studies at the University of Western Ontario in Canada.
Similarities stop there, however, says Susan Brownell, a professor of anthropology at the University of Missouri, St. Louis, currently in Beijing studying Chinese preparations for the Olympics. In the Olympic education campaign that the authorities have been running from primary school level to university, she says, "the Communist party is almost never mentioned, and nor is socialism."
At the same time, she and others point out, China is not the militaristic power bent on the physical elimination of an entire race and marching toward world war that Germany was when it welcomed the world's athletes in 1936.
A parallel that the International Olympic Committee (IOC) would prefer to draw is with the Seoul Olympics, where the South Korean military dictatorship allowed democratic elections shortly before the 1988 Games.
When China's bid for the Games was accepted in 2001, the then-executive director of the IOC, François Carrard, said, "Some people say, because of serious human rights issues, we close the door and say no. The other way is to bet on openness. We are taking the bet that seven years from now we will see many changes."
There have been few signs of such changes on the human rights front, and other observers point to Tokyo, where the Games were held in 1964, as a more apt parallel.
"The world felt a sense of amazement that a country laid so low in 1945 could present itself as a symbol of modernity," says Jeff Wasserstrom, a professor of history at the University of California, Irvine.
"China has also come back from a traumatic period," Professor Wasserstrom adds. "There is the same sense of potent expansion, of being in a league people had not thought they were in."
In the past, major controversies surrounding Olympic Games have been blown up by established governments: In 1980, US President Jimmy Carter led a Western boycott of the Moscow Olympics in protest of the Soviet invasion of Afghanistan the year before.
This year, "what is unique is that some very well-organized nongovernmental organizations have occupied a large space in the media" to protest China's policy on human rights, Tibet, and Darfur, creating controversy from the ground up, says Professor Brownell.
They have taken advantage of the Internet, "which offers more opportunities to those who want to protest," says Dr. Wamsley, and also benefited from a press more ready to cover political issues linked to sporting events.
In 1968, several hundred student protesters were killed by the Mexican police a few days before the Olympics opened. But Western journalists, almost all sports reporters, largely accepted the government's account that demonstrators had fired first and that only 15 people had died, an account that was later found to be untrue.
Beijing's security measures, tight though they will be, are unlikely to be as heavy-handed as the Mexico's response. But the Chinese are anxious to forestall another outbreak in a long tradition of individuals and groups using the Games as a platform to broadcast their political messages.
That tradition goes back to the Athens Games in 1906, when Irish triple-jumper Peter O'Connor climbed the flagpole to tear down the British flag, under which he had been obliged to compete, and wave the green flag of his country's independence movement.
In 1968, Mr. Smith and Mr. Carlos's Black Power salutes earned them expulsion from the Mexico Games for breaking rules about political gestures inside competition venues.
More tragically, at Munich in 1972, a group of Palestinians belonging to Black September took 11 Israeli athletes hostage, and killed two of them, demanding the release of Palestinian prisoners. A bungled rescue attempt killed the remaining nine Israelis and five of the Palestinians.
In 1996, Eric Rudolph set a bomb that killed one bystander and wounded 111 others in the Olympic Park in Atlanta. Mr. Rudolph said later that the attack had been designed "to confound, anger and embarrass the Washington government in the eyes of the world for its abominable sanctioning of abortion on demand."
Demonstrators will doubtless seek to exploit the opportunity that the presence of 15,000 journalists will give them to publicize their causes in Beijing. But the government can hope that the sports will eventually overshadow the troubled run-up to the games.
"Unless something really terrible happens... the Games will be OK when they begin," predicts Mr. Wallechinsky. "The day that competition begins, the entire focus will move to the athletics."