To be fair they were totally right that going to war would be a terrible idea but they did it anyway - given that World War 1 pretty much killed off the ruling aristocracy, lead to countless suffering, and stagnation. If they were smart it would have prevented the war but as Bismark predicted it all blew up over a fool thing in the Balkans.

It is like MAD - the assumptions are based upon rational actors which is why they are terrified of proliferation beyond just others getting in their clubhouse.