Will taekwondo achieve what diplomacy hasn’t?

North Korea, having ignored South Korean requests to participate for months, will send athletes, cheerleaders, and taekwondo-demonstration teams to next month’s Winter Olympics in Pyeongchang, South Korea. The agreement, which was announced Tuesday after the first meeting between the two countries in two years, could help reduce tensions caused by Pyongyang’s nuclear-weapons and ballistic-missile programs. But will it?

The development is a breakthrough. It was accompanied by the announcement the two sides would hold military talks to reduce tensions. But we’ve been here before.

The two Koreas marched together under one flag at both the 2000 and 2004 Summer Games, as well as the 2006 Winter Games. Those occasions were also hailed as historic breakthroughs, but Pyongyang and Seoul reverted afterward to their usual postures of mistrust, tension, and frequent reminders that the 1950-53 Korean War ended not in a peace treaty, but an armistice.

“I am always amazed when I hear people saying that sport creates goodwill between the nations, and that if only the common peoples of the world could meet one another at football or cricket, they would have no inclination to meet on the battlefield,” George Orwell wrote in “The Sporting Spirit,” the 1945 essay perhaps best known for describing sports as “war minus the shooting.” He added: “At the international level sport is frankly mimic warfare. But the significant thing is not the behavior of the players but the attitude of the spectators: and, behind the spectators, of the nations who work themselves into furies over these absurd contests, and seriously believe—at any rate for short periods—that running, jumping and kicking a ball are tests of national virtue.”

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.”

The Koreas may march together, India and Pakistan may yet play each other at cricket, Iranians might still cheer for the “great satan,” but all it takes is one missile test, one attack by militants, or one more threat directed at an ally, to end that goodwill and turn it into jeers, stadium riots, or worse.

As Orwell wrote in that 1945 essay, “I do not, of course, suggest that sport is one of the main causes of international rivalry; big-scale sport is itself, I think, merely another effect of the causes that have produced nationalism. Still, you do make things worse by sending forth a team of eleven men, labelled as national champions, to do battle against some rival team, and allowing it to be felt on all sides that whichever nation is defeated will ‘lose face.’”