Invading Normandy and bombing Nagasaki were solutions to end WWII. And we've not gone to war with Germany since, now, have we?
Some historians say that WW I and WW II were really one war with a 20-year peace interlude between them. The point being, it's the peace following the war that determines whether war will recur. I have a memory-fragment of some famous general saying "winning" the peace that follows a war is harder than winning the war itself.
But even so, 60 years of peace in western Europe is a drop in the bucket. If it lasts another 60 years, we may be onto something.