But any soccer hooligan will tell you that sports could just as well stoke tensions as defuse them—there is even a legend that attributes the brief war in 1969 between El Salvador and Honduras to a soccer match. (Historians attribute the conflict to land monopolization, as well as nationalism and overpopulation.)

Meanwhile, though, countries continue to rely on sports as a diplomatic tool, with limited success. Take India and Pakistan: The two countries have used cricket in the past for this purpose. But their relations are now so poor that India refuses to play Pakistan at the sport—except at international tournaments—citing its support of militant groups. The U.S. and Iran are another example. The Bush administration sent a team of American wrestlers to Iran in 1998 where they were warmly welcomed. Sporting exchanges continued through the Obama years—but relations between the Trump administration and Iran’s regime in Tehran are tense, and after Iranians were placed on the president’s travel ban, the Islamic republic denied visas to U.S. wrestlers.

That doesn’t prevent the U.S. State Department from viewing sports “as a way to transcend linguistic and sociocultural differences and bring people together.” A host of sports stars from Michelle Kwan to Shaquille O’Neal have served as envoys for the department. (Not to mention Dennis Rodman’s freelance diplomacy in North Korea.) Kwan traveled to China and other places as a public ambassador to meet with young people; O’Neal played basketball with Cuban children.

Sports can also effectively serve as a showcase for often ugly nationalism. Hitler used it as an effort to display his pretensions of Aryan superiority in the 1936 Berlin Olympics (though that effort was severely bruised by Jesse Owens, the African American sprinter who won four golds at the games). Palestinian militants used the Olympics in 1972 to kill Israeli athletes in Munich. Iranian athletes are ordered by their leaders to forfeit contests against their Israeli counterparts because they don’t see Israel as legitimate. At other times, sporting events are used to highlight grievances: The sporting rivalry between Japan and Korea is still haunted by Japan’s wartime actions on the Korean Peninsula, and Korean fans boo or drown out the Japanese anthem. In Spain, supporters of Catalan independence proudly brandish the logo of the football team FC Barcelona.

Michael Rubin, a resident scholar at the American Enterprise Institute, wrote in Foreign Policy in 2014: “Certainly, athletes often reach across diplomatic divides at international games, trading swag, pins, and jerseys. But when the final whistle blows, the lights dim, and competitors break their final handshakes, it is the same politicians who remain in charge.”

If anything, sports reflect a certain amount of goodwill between nations rather than being the cause of it. Even the best-known example of sports seeming to bring two nations closer—the ping-pong diplomacy in the early 1970s between China and the United States that was credited for President Nixon’s historic visit to China—was the result of months of quiet diplomacy involving Pakistan, then a pivotal American ally. As Chas Freeman, the veteran diplomat, recalled later: “For most people in the [State] Department, ping-pong diplomacy was minor but interesting evidence, from the Chinese side, of an interest in pursuing a relationship with the United States. In fact, it was the culmination of quite a bit of diplomacy, some of it known to the Department, to a few people, and much of it unknown.”