Political contentions have increasingly interfered with an avowed aim of the modern Olympics, that of fostering international amity. At the 1936 Olympics in Berlin, Adolf Hitler refused to recognize the achievements of Jesse Owens, a black American who won four gold medals. The 1972 games, held in Munich, West Germany, were marked by a tragedy growing out of political conditions in the Middle East. Members of an Arab guerrilla organization killed two Israeli athletes and took nine hostages, who were later killed along with five of the guerrillas and a West German policeman in a gun battle with police at a Munich airport. Olympic activities were suspended for a day to hold memorial services for the murdered Israeli athletes. The 1976 games, held in Montréal, were also marred by political issues, one of which involved China–Taiwan relations. The host Canadian government refused to allow the Taiwanese team to carry its flag or have its national anthem played at the games, and the Taiwanese thereupon withdrew. A second issue involved most of the black African nations. They demanded that New Zealand be excluded because one of its rugby teams had recently played in South Africa, whose racial policies these black African nations opposed. When their demand was refused, 31 nations withdrew their teams from the competition

 

The U.S., after much debate, withdrew from the 1980 games held in Moscow to protest the Soviet invasion of Afghanistan. About 64 other nations also boycotted. The USSR, citing doubts about security measures, withdrew from the 1984 games in Los Angeles; 15 other nations followed suit. One hundred sixty nations participated in the 1988 Olympics in Seoul, South Korea; the lone political controversy centered around North Korea's unsuccessful bid to serve as cohost.

The 1992 Olympics in Barcelona, Spain, reflected a changed political landscape: the 172 participating nations and territories included the Unified Team (with athletes from 12 former Soviet republics), a reunited Germany, and South Africa, which was allowed to compete for the first time since 1960.

Teams from 199 nations and territories took part in the 2000 Summer Olympics in Sydney, Australia. Three nations—Eritrea, the Federated States of Micronesia, and Palau—competed for the first time, and four athletes from East Timor participated as “Individual Olympic Athletes.” Also, North and South Korea entered the games under one flag, although they competed as separate countries.

A record 202 nations participated in the 2004 Summer Olympics in Athens, Greece, where the games were held for the first time since the original modern Olympiad 108 years earlier. It was the most expensive Olympic Games of all time, costing about $4.5 billion.