Charles Krauthammer demonstrates again why his columns are essential reading, in a piece on The Case for Fearmongering. (Hat tip: song_and_dance_man.)

Shortly after Hiroshima, wrote physicist Richard Feynman in his memoirs, “I would go along and I would see people building a bridge … and I thought, they’re crazy, they just don’t understand, they don’t understand. Why are they making new things? It’s so useless.” Useless because doomed. Futile because humanity had no future. That’s what happens to a man who worked on the Manhattan Project and saw with his own eyes at Alamogordo intimations of the apocalypse. Feynman had firsthand knowledge of what man had wrought — and a first-class mind deeply skeptical of the ability of his own primitive species not to be undone by its own cleverness.

Feynman was not alone. The late 1940s and ‘50s were so pervaded by a general fear of nuclear annihilation that the era was known as the Age of Anxiety. That anxiety dissipated over the decades as we convinced ourselves that deterrence (the threat of mutual annihilation) would assure our safety.

Sept. 11 ripped away that illusion. Deterrence depends on rationality. But the new enemy is the embodiment of irrationality: nihilists with a cult of death, yearning for the apocalypse — armed, ready and appallingly able.

The primordial fear that haunted us through the first days and weeks after 9/11 has dissipated. Not because the threat has disappeared but for the simple reason that in our ordinary lives we simply cannot sustain that level of anxiety. The threat is as real as it was on Sept. 12. It only feels distant because it is psychologically impossible to constantly face the truth and yet carry on day to day.

But as it is the first duty of government to provide for the common defense, it is the first duty of any post-9/11 government to face that truth every day — and to raise it to national consciousness at least once every four years, when the nation chooses its leaders.

Fearmongering? Yes. And very salutary. When you live in an age of terrorism with increasingly available weapons of mass destruction, it is the absence of fear that is utterly irrational.