He quotes William Shirer's journal entry for August 10, 1939:
How completely isolated a world the German people live in. A glance at the newspapers yesterday and today reminds you of it. Whereas all the rest of the world considers that the peace is about to be broken by Germany, that it is Germany that is threatening to attack Poland over Danzig, here in Germany, in the world the local newspapers create, the very reverse is being maintained. (Not that it surprises me, but when you are away for a while, you forget.) What the Nazi papers are proclaiming is this: that it is Poland which is disturbing the peace of Europe; Poland which is threatening Germany with armed invasion, and so forth. This is the Germany of last September when the steam was turned on Czechoslavakia. For perverse perversion of the truth, this is good. You ask: But the German people can't possibly believe these lies? Then you talk to them. So many do.RI then notes that Shirer also said most Germans were opposed to the war, feared it, and didn't really expect it to come. But it came.
As RI points out, it only takes a few people in key positions to make a war happen, regardless of how insane a misadventure it seems to everyone else. "I've seen nothing to suggest that real men no longer want to go to Tehran."