It is a fact that, in principle, Utilitarianism cannot be self-defeating. Since it does not specify a particular strategy or set of means to achieve its goal (the greatest possible good), any strategy or set of means which failed would be rejected.
In practice, Utilitarian agents are self-defeating with depressing regularity. The most powerful and ruthless people who seek some good regardless of the constraints of common-sense morality seem almost always to end up creating far more harm than good - even in their own terms. No one could be more calculating and unimpeded in pursuit of a goal than the great dictators of the last couple of centuries, but, despite the oceans of blood they spilt, their imperial or ideological projects came, in the end, to nothing. In some cases they had thoroughly misguided goals; in others, their disregard for conventional morality created a reaction which eventually defeated them. Both show the dangers of Utilitarianism in practice: it encourages the idea they you can dream up your own vision of the good and then promote it with complete disregard for the collateral damage - having worked out first, to your own satisfaction, that this damage will be less than the good you will bring about. Such calculations are invitations to self-delusion, not to say megalomania.
One enduring debate among historians is the value, or lack of it, of one of the greatest crimes committed by the Allies in the 2nd World War, of conventional area bombing. I was interested to see a new book on the subject, which concludes that the huge resources devoted to this would have been better used elsewhere, from the point of view of winning the war as quickly as possible: that is to say, even leaving aside the horrendous carnage it created of non-combatants.
The case of the nuclear bombing of Japan is even more controversial as to its effectiveness, though even more straightforwardly criminal in its targeting of civilians.
Here are some quotations from the Economist's review.
The Bombing War: Europe 1939-1945. By Richard Overy. Allen Lane; 852 pages; £30.
The failure of Germany’s first big bombing campaign against Britain, following the allies’ unexpectedly sudden collapse in France in 1940, was in some ways typical of what came later in confused ends and inadequate means. Two things above all ensured that all the early attempts at strategic bombing (whether by the Germans, the British or the hopelessly ill-equipped Italians) were far less effective than anyone had expected.
The first was the near impossibility, given the technology then available, of landing a meaningful concentration of bombs near any target other than a large city; in 1941 only one in ten Royal Air Force (RAF) bombers got within five miles of their targets in the Ruhr valley. The second was the unforeseen resilience of well-organised societies to withstand bombing without suffering either moral or economic collapse. Shelter was found for people who had lost their homes, repairs to infrastructure were quickly made and industrial production temporarily shifted if necessary. Although more than 40,000 people died during the eight months of the Blitz and in London about 1m homes were damaged or destroyed, there were no riots and war production increased steadily. People suffered, but the majority got used to it.
Despite this experience, Britain’s Bomber Command under the brutally single- minded Arthur Harris, never doubted that “area bombing”, a euphemism for attacking cities indiscriminately. And he never lost his belief that if you killed enough German workers you would win the war. Yet even when the RAF in 1942, closely followed by the US Army Air Force, began to put together the famous “thousand bomber” raids that were supposed to “knock Germany out of the war”, German war production continued to ramp up and the Nazi regime never came remotely close to losing political control.
Mr Overy’s final verdict, however, is damning. He argues that “strategic bombing proved in the end to be inadequate in its own terms for carrying out its principle assignments and was morally compromised by deliberate escalation against civilian populations.” Nor has it left any real legacy. It was rapidly rendered redundant by the overwhelming but (since 1945 at least) unusable destructive power of nuclear weapons. More recently, bombing has come full circle. Precision-guided munitions now allow Western air forces to hit military targets while leaving even nearby civilians often largely unscathed—the precise opposite of what prevailed during the second world war.