When the Greek captain Menelaus was tempted to spare the life of an incapacitated opponent on the killing field outside the walls of Troy, his brother Agamemnon rebuked him: “Once in our hands not one should squirm away / from death’s hard fall! No fugitive, not even / the manchild carried in a woman’s belly! / Let them all without distinction perish, / every last man of Ilion, / without a tear, without a trace!” And in the end, as Homer’s listeners knew, that is exactly what would happen. Throughout history, every war has been a total war for those unfortunate enough to be trapped at the epicenter of violence, where “all without distinction perish.”

In the modern era, new technologies have greatly amplified war’s destructiveness. The most lethal new weapon was the airplane because it transformed the spatial dimensions of war by extending the battlefield beyond the zone where opposing armies met. Because an enemy’s entire society was now at risk, the concept of total war had a new and more terrible meaning.

Airplanes were first used in combat by the Italians, who dropped explosives on Arab tribesmen in Libya in 1912. During the First World War, both sides bombed civilian targets, but their efforts did relatively little damage and were without strategic significance. During the 1920s and ’30s, as the quality of aircraft steadily improved, advocates of airpower argued that strategic bombing could enable combatants to avoid the western front’s catastrophic stalemate. Within a few days, these theorists promised, intensive air strikes would shatter the fragile institutions of modern societies, disrupt the enemy’s war effort, isolate its army in the field, and compel it to capitulate. Widespread fear of bombardment from the air was an important part of the political climate that encouraged European statesmen to appease Hitler in the late 1930s.

In fact, the bombing of civilian targets in the west did not begin until the ninth month of the war, when the Germans fire-bombed Rotterdam in May 1940. Thereafter, the air war steadily escalated, as first the Germans and then the British and Americans used air power to try to break the morale and destroy the productive potential of their enemies. From the defeat of France in the summer of 1940 until the invasion of France in June 1944, the bomber was the Western allies’ chief weapon against Germany. While millions of Soviet soldiers and civilians faced the Wehrmacht on the ground, thousands of British and American airmen fought in the sky above German cities. This was the contribution to which Churchill and Roosevelt pointed when Stalin demanded that they open a second front.

Until recently, our view of the bombing campaign was almost exclusively from the vantage point of the airmen, whose sacrifice and skill has been celebrated by scores of monographs, memoirs, and movies (including at least one masterpiece, Twelve O’Clock High, starring Gregory Peck as General Frank Savage). Historians analyzed bombing strategy and tactics and debated its military effectiveness, but said little about the German civilians who lost their homes and lives. After 1945, the Germans themselves were curiously silent about their experiences. As W. G. Sebald pointed out in 1997, the fact that “about six hundred thousand German civilians fell victim to the air raids, and that three and a half million homes were destroyed” had been largely ignored by postwar scholars and writers. The extraordinary suffering caused by the bombing “seems to have left scarcely a trace of pain behind in the collective consciousness.”

Jörg Friedrich’s The Fire, originally published in German in 2003, is a sustained effort to measure the scale of destruction and to recapture the intensity of this pain. Now Friedrich’s work is available to an English-speaking audience in this serviceable, if uneven and sometimes awkward, translation.

The Fire contains a number of striking statistics and analyzes the technological basis of incendiary bombing, but most of Friedrich’s book seeks to convey the horror of the bombing with examples, a relentless litany of suffering that describes the air war’s impact on people, structures, and things. In almost unbearable detail, we read how men, women, and children cowered in shelters throughout the night and then emerged to find their familiar world a vast pile of rubble and smoking debris. Many were buried alive when their shelters failed; those caught in the firestorm were reduced to ash or a few grisly body parts. The bombs did not discriminate: they struck young and old, rich and poor, Nazi fanatics and foreign slave laborers. Mothers watched their children die, children wandered in search of parents gone forever. As we read about how the bombs turned one German city after another into an inferno, we are reminded why our ancestors chose fire when they tried to imagine the anguish of eternal damnation.

There is no doubt that the air war was evil. Surely we cannot believe that the victims—including tens of thousands of children—deserved what they got simply because they were Germans. It is, after all, just this sort of thinking that made Nazism so wicked. We might readily accept Friedrich’s view that the air war was evil, but was it a crime, comparable in some ways to the Nazis’ own? Here Friedrich moves cautiously. He is not an apologist for Nazism, but he cannot resist what we might call the temptation of equivalence. For example, he tells us that Pastor Fritz von Bodelschwingh, the director of an asylum for mentally ill children, was able to save his patients from the Nazi euthanasia campaign but not from Bomber Command, thereby suggesting that there was a clear parallelism in the two projects.

Friedrich leaves little doubt that he regards the bombing as unjustified, even criminal, but he never directly poses the counterfactual questions: What were the alternatives? What would have happened had the Allies decided to do their best to spare the lives of German civilians? We cannot make this question easier to answer by maintaining, as some historians have done, that the air war did not contribute to the Allies’ victory. Of course it did. While the bombing did not fulfill its advocates’ inflated aspirations, it damaged the Germans’ war effort in a number of important ways, most significantly by forcing them to expend their limited supply of experienced fighter pilots in a desperate attempt to protect their cities. Had the Germans been able to use the men and resources they deployed against the bombing for other purposes, they could have prolonged the war on the ground for months, perhaps years. Would fewer German civilians have died and fewer German cities been destroyed in a war lasting until 1946 or 1947? And as long as the ground war went on, the Nazis would have continued their murderous campaign against Jews, gypsies, and anyone else they considered enemies of the Reich. Assessing the morality of the bombing requires us to weigh the consequences of the alternatives, and to ask whether the means used were proportionate to the good that was sought.

“The problem of end and means,” Jacques Maritain wrote, “is a basic, the basic problem in political philosophy.” The problem, he continued, can be solved in theory, but in practice the solution “demands from man a rare kind of heroism and hurls him into anguish and hardship.” For the practitioners of war, the problem of ends and means is especially difficult because in war the means are always evil: violence is never contained, innocent blood is always shed. Except for those who reject war entirely—an attractive but difficult position to maintain—the moral problem of war is whether its purpose can justify this evil. Few wars, I believe, meet this test, but the Second World War is one of them.

British and American advocates of strategic bombing were often an arrogant, callous, and hard-hearted lot. Their extravagant claims and cruel celebrations of mass bombing are morally repellent. (War, St. Augustine says somewhere, can be justified; the love of war is always evil.) Nevertheless, the men who ordered the bombing were right to recognize that when faced with the absolutely essential and morally compelling task of defeating Hitler’s Thousand Year Reich, the air war was a necessary means—evil, as Friedrich so eloquently insists, but necessary nonetheless.