Ilya Somin at Volokh Conspiracy contrasts American sports fanaticism with that in Europe, and finds ours lacking (our fans almost never kill each other over games):
Where do newspapers come in? I read a report a few days ago, I think from a newspaper conference in Europe, that's relevant. As I remember it, European newspapers look at US papers and see lots of weak, local papers as compared to their setup where you have fewer, more national papers. For example, in France the Paris newspapers dominate the country; similarly in Britain the London papers are dominant. The closest we come is having USAToday, the Wall Street Journal and NY Times, but even those papers don't have the influence of the Times (of London). So the Euro papers see the problems US papers are having with the Internet and currently don't have the same problems, but anticipate they may down the road.Many European and especially Latin American soccer teams are also closely associated with governments. This often allows repressive and corrupt regimes to obtain propaganda benefits from the teams' victories. For example, the repressive Brazilian and Argentinian military governments of the 1970s increased their public support as a result of their national teams' World Cup victories in 1970 and 1978. In Europe, Mussolini, Franco, and the communist government of the Soviet Union derived similar benefits from their teams' successes. On a lesser scale, incompetent or corrupt local governments in Europe sometimes benefit from the victories of local clubs.
In the United States, by contrast, pro sports rivalries are based on geographic divisions that have little or no connection to deeper social antagonisms over race, religion, or political ideology. As a result, even the most heated US sports rivalries, such as the Red Sox-Yankees rivalry, rarely result in violence between fans of opposing teams - and never in the form of the large-scale soccer riots that we sometimes see in Europe, Asia, and Latin America.