Does it help to know history?
What should, say, the advisers to Lord Grey, the British foreign secretary, have told him a century ago? Surely something like: Let’s not lose our heads; the Germans are a growing power who can be accommodated without losing anything essential to our well-being and, perhaps, shaping their direction; Serbian nationalism is an incident, not a cause de guerre; the French are understandably determined to take back Alsace-Lorraine, but this is not terribly important to us—nor to them either, really, if they could be made to see that. And the Ottoman Empire is far from the worst arrangement of things that can be imagined in that part of the world. We will not lose our credibility by failing to sacrifice a generation of our young men. Our credibility lies, exactly, in their continued happy existence.