All of the centuries-old reasons to be confident in American resiliency have been put into doubt. Adam Smith said of successful nations that they have a lot of “ruin” in them. He meant that a dissolute, leisured and ahistorical generation has to waste a lot of its generous inherited wealth before it runs out. We are learning how much of the wealth will be left. And the rest of the world is watching — some with glee, others with horror.