Sometimes one man can make a big difference. In 1980, it was US President Jimmy Carter. His US-led Western boycott damaged the Moscow Olympics and led to a retaliatory boycott of the 1984 Los Angeles Olympics. In 1990, it was USSR President Mikhail Gorbachev, whose reforms broke up the old Soviet Union and dismantled its sports machine. On the other side of the ledger is Nelson Mandela whose actions made sport better.
For 27 years, he lay captive but as the years rolled on, he became a spearhead in the war against apartheid in South Africa. The world of sport had long banned South Africa from international competition. His quiet resolute dignity grew to become a symbol of resistance. Soon after his release, he became president of South Africa and brought an end to apartheid.
It was a political victory over an evil system of segregation, but it was also a victory for sport. South Africa had produced fine athletes in a wide range of sports but apartheid had forced some like the ill-fated distance star Zola Budd to seek other countries as vehicles to international competition.
It was brilliant to see the return of South Africa to the Olympic Games in 1992. Appropriately, its first two Olympic medal winners in the new era were a white South African Elana Meyer in 1992 and black South Africans Josiah Thugwane and Hezekiel Sepeng in 1996.
This is the Mandela legacy to sport. South Africa had been away from the mainstream of sport because of apartheid. His persistence made the sporting world more whole.
The Carter boycott robbed athletes and fans of two Olympic opportunities to see the best facing the best for the ultimate prize in sport. In 1980, Renaldo 'Skeets' Nehemiah was approaching the height of his power as a 110 metres hurdler and would have been favoured to beat eventual gold and silver medal winners Thomas Munklet of East Germany and Alejandro Casanas of Cuba.
The boycott broke Skeets' heart. After breaking the historic 13-second barrier in 1981, he left the sport for the NFL.
The Gorbachev reforms dismantled the formidable Soviet sports machine and turned the lives of many sportsmen upside down. Very few in the old Soviet Union and the rest of the Soviet bloc found sponsorship right away. Without the support they were used to, many faded away.
A few, like pole vaulter Sergey Bubka, soared to sporting and financial heights in the brave new play-for-pay world.
Mandela gave South Africa back to cricket and notably rugby where the Proteas became world champions at home in 1995. That story was eventually told in the movie Invictas.
That victory accelerated the multiracial integration of South Africa. Its integration into international sport was complete in 2010 when South Africa hosted the World Cup.
Its successful bid to host football's biggest event was boosted by a presentation by Mandela himself.
Track and field got Mayer, Sepeng, pole vault ace Okkert Brits, 1997 javelin world champion Marcus Corbett and a pair of high jump world champions in Jacques Freitag and Hestrie Cloete. Add 2002 World Junior 400 hurdles champion Louis van Zyl to the mix, and you see how much South Africa has added to track and field in particular.
Among them was Llewellyn Herbert, the 2000 Olympic bronze and 1997 World Championship silver medal winner in the 400 hurdles. He added his own personal bit of colour to track meets by facing backwards before his races.
Cricket fans have probably benefited the most from South Africa's return. Like Budd, the late Tony Grieg found a sporting home in England and eventually captained his adopted country. Even though some like Kevin Pitterson and Matt Prior continue in Grieg's footsteps, the restored South Africa has given cricket the likes of Jacques Kallis and a team that was recently ranked number 1.
More needs to be done to have fully integrated teams, but it's great to have South Africa back. We all have Mandela to thank for that.
Sport, however, is just one small part of his legacy. The biggest and best part is the lesson his dignity taught the world. One man can make a difference - if he resolutely does the right thing.
Hubert Lawrence has made notes at track side since 1980.