Despite the many negative comments in the previous posts, I think you only have to look as far as the Olympic Games to recognize that international harmony can exist between most nations. The recent Games were a great example of how thousands of athletes from hundreds of nations can come together in the spirit of athletic camaraderie. These athletes develop life-long friendships while proudly representing their widely diverse nations. Other positive examples include the recent Notre Dame football game in Ireland and the regular NFL and Major League baseball games played in Europe and the Far East. These games bring new fans to the sport and a better understanding of baseball and football in areas where other sports (specifically soccer) rule.
Yes and no--but a little bit more no than yes. The biggest international sports event, the Olympics, have often revealed high tension between countries.
In 1936, many American and international leaders tried to organize a boycott of that year's Olympics, to be held in Nazi-ruled Germany. One of the important policies of the Olympics is that the teams can't discriminate on the basis of race or religion--a rule that Nazi Germany was obviously breaking. Unfortunately for boycott supporters, Avery Brundage, the president of the International Olympic Committee, was fairly anti-Semitic himself, and faught hard against a boycott. (you can read more about that on the US Holocaust Memorial Museum website http://www.ushmm.org/wlc/en/article.php?ModuleId=10007087).
In 1976, most of Africa boycotted the Olympics to protest New Zealand's having broken the unspoken agreement among a lot of teams to avoid playing with South Africa while South Africa continued to oppress its black citizens under apartheid (that's about 15 years before Invictus, if you've seen that movie!)
1980 (Moscow) and 1984 (L.A.), the US and the USSR, respectively, boycotted each other's Olympics.
This year, there were some problems with the Lebanese judo team refusing to train alongside the Israeli team. They made the olympic event coordinators put up a division through half the space so that they could train separately. You can read more about that in a Telegraph (UK newspaper) article here http://www.telegraph.co.uk/sport/olympics/judo/9433680/London-2012-Olympics-Lebanon-judo-team-refuse-to-train-alongside-Israel.html
On the other hand, North and South Korea have been at war for sixty years, and they regularly compete against each other without incident. And the fundamentals of the Olympics are peaceful and noble--in ancient Greece, warring city-states were required to adhere to a ceasefire (a temporary peace, called ekecheiria) for the duration of the Games, so that athletes could travel and compete safely.
If sports always contributed to international understanding and peace, we would not have as much conflict as we do. For example, India and Pakistan often play cricket against one another. This has not led to peace and understanding. During the Cold War, the Olympics were held every four years. They contributed to peace and understanding so well that they were boycotted in 1980 and 1984 (by the US and its allies and then the Soviet bloc) due to Cold War tensions. At that time, sports were really being used as another arena in which to compete for global dominance. Victories (see US Hockey team, 1980 Olympics) were seen as expressions of national worth. This does not show much in the way of evidence that sports leads to harmony and understanding.
Sports do not always contribute to international harmony and understanding. In fact, I would say that rarely do sports contribute to these concepts. Consider some international sports--soccer, skiing, gymnastics, skating, and etc. The competitive nature of sports would seem to be an obstacle to harmony and understanding. When you factor in language barriers, it would seem that the blockage becomes even bigger. That does not mean that individual competitors cannot be good will ambassadors for their sports. In fact, many individual competitors do go on to promote these fine ideas. The sport, however, does not.
I think that in the case of the Olympics, more often than not the games have shown great rivalry and perhaps in some cases hatred towards other countries. With so many countries competing at such a high level, it gets very intense for the athletes, the coaches, and of course, the fans. I do not believe these have contributed much to international peace and harmony.
On the other hand, there are some sports that I think might be doing a bit better on this topic. While it is difficult to say that any sport creates peace and harmony (it is a sport after all), I believe that the NFL and the NHL are two leagues that try to cater to different types of fans. For example, the NHL has not only American hockey teams, but Canadian as well, which contributes to both rivalries and a sense of closeness to two neighboring countries. Also, the NFL has at least one game every year in England to give English fans a chance to see their favorite team play without having to leave the country.
It should, as all sports have specified rules and every country has athletes that are excellent and can be trained without a great deal of expense. So sports should create a level playing field, equalizing all people and all places. Unfortunately, it doesn't.
To many people take sports to seriously, missing the enjoyment of a well executed play or the wonder of a well conditioned person and only seeing that it wasn't "their" team or athlete. Some will try to actually interfere, throwing things on the field or shouting obscenities at the players, trying to distract and disrupt the game rather than left players compete. When this happens between teams from different countries, it creates international disharmony and discord.
Let's look at what happened between India and Pakistan recently in Cricket. Some terrorist in Pakistan killed an Indian Cricket player and then several in India were clamoring for boycotts of all Pakistan or, in a few cases, war. Most Pakistanis were as horrified as the Indians and most Indians realized it was not related to the whole of Pakistan, but it was being used to disrupt any hope of harmony across the international lines.
nternational harmony? The answer in one word is "no". Unfortunately sports which are seen around the world are utilized by too many politicians to promote their political agenda, which is not always harmonious. Should and could sports contribute to international harmony, most definitely.