I like your use of historical examples in your post, but I think World War I (or 1913) is an iffy example. World leaders had known conflict was possible for a

I like your use of historical examples in your post, but I think World War I (or 1913) is an iffy example. World leaders had known conflict was possible for a long time and had been preparing for it - the build up of alliances both was an example of this and the ultimate cause of war. Conflicts in the Balkans preceded WWI by several years. If you think Trump is crazy try Wilhelm who was widely known as an egomaniac. The shopkeepers may not have known what was coming but the world leaders certainly did. We don't have anything that could jump start a world war in the same way. In fact, it's more likely that we'd have seen conflict with Russia via Clinton than we would with Trump, and that would be our main threat of nuclear war today. As far as conventional war goes, there's nothing like pre-WWI in place with America being the clear global hegemon. Neither China nor Russia have the military to engage in anything but localized conflicts.