I’ve written a number of times over the years about the fact that Americans mostly believe that the post-World War II world order is the normal state of things. Of course, it is not. The last 80 years are unparalleled in global history for their general prosperity, lack of great power wars, a fairly predictable system of global rules. One has to say the obligatory caveats about all the ways the United States honored its values and rules in the breach, the slow run of proxy conflicts it participated in or fomented around the world. But these caveats only serve to illustrate the larger point in a paradoxical way. Things can always get worse and getting worse — conflict, instability, mass death — are the normal order of things in world history. Even a thin appraisal of the American ascendency shows its close to uniqueness in this regard.