Hitherto a doctrine of American celebration and optimism, liberalism would now become a scowling indictment: Kennedy was killed by America’s social climate, whose sickness required “punitive liberalism.” That phrase is from James Piereson of the Manhattan Institute, whose 2007 book “Camelot and the Cultural Revolution: How the Assassination of John F. Kennedy Shattered American Liberalism” is a profound meditation on the reverberations of the rifle shots in Dealey Plaza.

The bullets of Nov. 22, 1963, altered the nation’s trajectory less by killing a president than by giving birth to a destructive narrative about America. Fittingly, the narrative was most injurious to the narrators. Their recasting of the tragedy in order to validate their curdled conception of the nation marked a ruinous turn for liberalism, beginning its decline from political dominance.

Punitive liberalism preached the necessity of national repentance for a history of crimes and misdeeds that had produced a present so poisonous that it murdered a president. To be a liberal would mean being a scold. Liberalism would become the doctrine of grievance groups owed redress for cumulative inherited injuries inflicted by the nation’s tawdry history, toxic present and ominous future.