Long term, you just need to look at the past 200 years to see what the "short term view" about the benefits of nationalism has led to ...

I don't see nationalism as to blame for those things. There are certainly MANY factors that were involved with what happened in the past 200 years in Europe. I don't see nationalism as the cause. I do see it as an EXCUSE some people that were pushing many other IDEAS would use to try to justify their actions. Yet ultimately that is not nationalism. That is imperialism. There is a difference.