We're rapidly closing in on the centennial of the outbreak of World War I. The Great War is like an ugly bug. You want to look away but are too fascinated to. It appears as though all of the European belligerents underwent a kind of inversion experience that turned the rational calculus of war on its head. The more lives and treasure armies spent in battle, the more commanders, pressure groups, and rank-and-file citizens wanted out of the effort. The more they demanded, the greater resistance they provoked from the enemy, and the more the bloodletting on the Western Front dragged on. No one appeared willing to abandon the sunk costs of war, as economics would mandate. Political leaders who might have done so proved too weak-willed to resist popular and military sentiments. Buffeted by passions and bereft of strong leadership, Europe stepped through the looking glass.
Carl von Clausewitz opines that the value a society assigns its political goals governs how much effort it expends to obtain those goals. That is, it determines the rate at which the combatant invests lives and resources in the endeavor, and how long it will keep up that rate of expenditure. Makes sense, doesn't it? Rational actors decide what price they're prepared to pay for something, and they cancel the sale if the seller raises the price above that level. But again, Clausewitzian cost/benefit logic presupposes a kind of sobriety that was conspicuously absent from European capitals until late in the day, when statesmen like Georges Clemenceau and Woodrow Wilson restored some semblance of rationality to the Allied cause.
In a real sense, then, the mounting "magnitude" and ever-longer "duration" of the war effort — how much the belligerents spent and for how long — drove the value European decisionmakers assigned their cause. If so, this mental reversal also negated the corollary to Clausewitz's rational calculus, namely that leaders should look for a graceful way out of an enterprise whose costs have grown unbearable. If there's no upper bound on the expenditure of national resources, whence do you summon the discipline to cut your losses?
The baneful effects of flouting cost/benefit logic were felt well beyond the battlefield. I think the decoupling of costs from benefits helps account for the surreal feeling you get from reading about the Great War. It may also help explain the black, apocalyptic mood that gripped European populaces during the interwar years, as deftly recounted by Richard Overy in The Twilight Years. Doomsaying was commonplace in that age. It was the era when the dystopian novels of Aldous Huxley appeared, when George Orwell chronicled the failings of British imperialism in Burma and his life as a bum on the streets of London and Paris, and when radical ideologies took hold among the resentful and dispossessed.
Such is the cultural and social backsplash of abandoning the rational calculus of war. That potential for malign consequences is worth remembering.