The United States this week announced a diplomatic boycott of the Beijing Winter Olympics in February, a move that was quickly followed by Australia, Britain and Canada.

Diplomacy is by its nature byzantine, and sometimes secretive as well. We’ll try to get to the bottom of what it all means.

What is a diplomatic boycott?

Those who remember the 1980s may think of an Olympic boycott as countries staying home, athletes and all. But the U.S. diplomatic boycott will preclude only government officials from attending. Typically, high-ranking officials from many countries attend the Games, which are among the biggest international gatherings outside of the United Nations and major summits.

What reason did the U.S. give for the boycott?

In announcing the decision, Jen Psaki, the White House press secretary, cited “genocide and crimes against humanity” in Xinjiang, a northwestern region of China. The Chinese government has cracked down harshly on Uyghurs and other predominantly Muslim ethnic minorities in that region, including mass detentions and forced use of contraception and sterilizations.

Calls for an Olympic boycott sharpened after Peng Shuai, a Chinese tennis star, accused a former top government official of sexually assaulting her. References to her accusation were quickly scrubbed from the internet in China, and she disappeared from public view, prompting athletes and others around the world to post, “Where is Peng Shuai?” Peng was later seen in several short videos shared by Chinese state media journalists on Twitter. The International Olympic Committee said it called her twice, but questions were raised about how freely she was speaking.

Is the boycott controversial in the U.S.?

There has largely been support for the move. If anything, the criticism has come from Republicans who say the decision does not go far enough. Senator Tom Cotton of Arkansas has said the United States “should fully boycott the genocide Games in Beijing.”

Does it mean anything for U.S. athletes at the Olympics?

Although the hostility between the nations may make for some uncomfortable moments for the American delegation in Beijing, there are not expected to be any significant effects. American athletes are to travel to China and compete in their events as scheduled.

Are Olympic athletes speaking out about China?

Some have. Evan Bates, an American ice dancer, said in October: “Speaking on behalf of all the athletes, I can say human rights violations are abysmal, and we all believe that it tears the fabric of humanity.” He added, “My answer could be applicable to human rights at large, but if you’re asking what’s happening in China regarding the Muslims, it’s terrible, it’s awful.” Some others have echoed his sentiments.

The International Olympic Committee has always steadfastly asserted that the Games are nonpolitical. As such, it has strict rules about athletes protesting while at the Games.

Are any prominent athletes not attending the Games in protest?

At this point, no. Even those top athletes who have condemned human rights abuses say they plan to compete at the Games.

Is there a precedent for a diplomatic boycott of the Olympics?

In 2014, President Barack Obama, Vice President Joseph R. Biden Jr. and Michelle Obama, the first lady, all skipped the Sochi Olympics in Russia. France and Germany also did not send top-ranking officials. Although it was not a full-fledged diplomatic boycott, the move was seen as a rebuke of Russia’s crackdown on gay rights and was also possibly motivated by Russia’s giving political asylum to Edward Snowden, who leaked classified documents about American spying.

What other boycotts have happened in past Olympics?

The most prominent boycott came in 1980, when more than 60 countries, led by the United States, boycotted the Summer Games in Moscow because of the Soviet Union’s invasion of Afghanistan the previous year. The boycott crippled the fields in many events at the Games, and also incensed American athletes, many of whom lost their only chance to participate at an Olympics.

In 1984, the Soviet Union led more than a dozen countries in a boycott of the 1984 Games in Los Angeles. Although the cited reason was security concerns, there is little doubt the move was essentially a reprisal for the 1980 boycott.

While a handful of nations had boycotted for various reasons at earlier Games, the first major boycott of an Olympics came in 1976 when about 30 mostly African nations sat out the Montreal Games. They contended that because a New Zealand rugby team had toured apartheid South Africa, New Zealand should be barred from the Games.

So no boycott of the Nazi Olympics? Really?

In 1936, the Games went to Germany, then under the control of Hitler’s Nazi Party. Some sports officials, and some politicians, including Mayor Fiorello La Guardia of New York City and Gov. Al Smith of New York, advocated boycotting the Games. But Olympic officials pushed hard against a boycott, with familiar arguments about separation of politics and sports.

Avery Brundage, who was president of the U.S. Olympic Committee, called the boycott plan a “Jewish-Communist conspiracy.” (He went on to lead the International Olympic Committee until 1972.)

In the end, U.S. sports officials chose to send a team to Berlin in a close vote.

Have boycotts been effective?

The boycott of the Moscow Games did not appear to have any effect on Soviet foreign policy; troops from the country remained in Afghanistan until 1989.

An international consensus seems to have emerged that sweeping boycotts that include athletes are ineffective and serve only to penalize sportsmen and women. Senator Cotton notwithstanding, few Olympic or government officials are seriously considering preventing athletes from attending the Beijing Games.

While boycotts may not change policy, they do run the risk of reprisals, as was seen in 1984. Sure enough, Chen Weihua of China Daily, a state media publication, has called for China to boycott the Summer Olympics in Los Angeles in 2028.