The events of September 11, 2001, put that possibility forever into the past. The George W. Bush who had been skeptical of nation-building became the George W. Bush of the democracy project. The peace dividend evaporated, along with the peace. The nation was at war, and the Long War, like the two world wars, bred radicalism — radicalism that ran hard in both directions. But the world wars ended. The Long War does not.

The trauma of 9/11, the divisions of the Iraq War, and the fearful disorientation of the financial crisis left Americans agitated and anxious — but not in a way that put them in the mood for another return to normalcy. The pendulum began to swing madly: The trauma of the Bush years begat the Obama presidency; the radicalism of the Obama presidency begat Trump; the radicalism of Trump (which is not, for the most part, a matter of policy) begat . . . much that is undesirable: Alexandria Ocasio-Cortez, “resistance,” and the mainstreaming of socialism as a basic current of the Democratic party; Bernie Sanders and Elizabeth Warren in a crazypants radicalism arms race over whether we should confiscate the accumulated savings of the affluent at a rate of 2 percent a year or at a rate of 8 percent a year; a turn toward a politics of implacable hatred and demagoguery in both of the major political parties.

It is sobering to realize that there are young Americans serving in Afghanistan today who had not been born on September 11, 2001, who have only known post-9/11 politics and a post-9/11 America, with all the angst and paranoia that goes along with them. This profoundly abnormal period in our history is their normal, the only world they have ever known.