A conflict in 20XX, in which the international community declared war on Switzerland for decades of hoarding dirty money of third-world dictators and crime lords. The invasion was a bloody affair, almost ending in the use of [cobalt bombs] by the Swiss "gnomes." However, the world won and thus war was abolished forever.
Of course, the fact that the U.N. becomes uber-prominent, the national superpowers apparently declining to the point that they match each other, and everyone forgetting about ethnic/social/religious reasons for fighting in favor of saving the environment helped, as well.
Reading this in the early nineties, it seemed a rather far-fetched notion that the world would unite against Switzerland (of all places!!) and found itself confronted with a lot more than was bargained for.
Brin comments, in the afterword, that he deliberately added something screwy because that is, indeed, how history often plays out: something left of field which is totally unpredictable.
Who, in 1989, would predict that the 2000 US presidential election would be effectively decided by a partisan decison by the US supreme court? (the consequences are a hot topic for discussion, and a full assessment would probably blow this site's memory limit!)
(It wasn't Brin, but Heinlein, writing even earlier, who predicted the election of an authoritarian religious zealot in 2012. It doesn't seem so far fetched in 2006).
Aside from the likelihood of a war on Switzerland, the feasibility of a Swiss Navy (and of a landlocked people becoming a maritime people) is an interesting possibility. As a general rule, the Swiss have proven capable and adaptable, so perhaps this is within their ability. It would be sad, however, to give up all those lovely mountains.
(... it would also suggest some *serious* melting of polar ice caps!)
In 2008, the Swiss people appear to becoming more rather than less open (see the recent poll rejecting a call to handle citizenship applications in secret). A Helvetian war is unlikely. However, the SecrecyUprising that led to it is another matter.
(See here for details)