Each year at this time — the anniversary of the bombing of Hiroshima — the world pauses. The pause is less to mourn the dead than to debate a moral question: whether the bombing was justified and, by extension, whether the United States unnecessarily slaughtered tens of thousands of people on Aug. 6, 1945. The debate rarely focuses on a careful analysis of war and morality and is more frequently framed by existing views of the United States. The debate is rarely about Hiroshima or about World War II. It is a debate about the moral character of the United States. This is not an illegitimate subject, and Hiroshima might be a useful point with which to begin the debate. But that isn’t possible until after we consider the origins of Hiroshima, which can be found in the evolution of modern warfare.
Innovations in Industrial Warfare
Warfare became industrial for a simple reason. The introduction of firearms brought to the battlefield a weapon with tremendous strength and an overwhelming weakness. The strength was the ability to kill or disable an enemy at distances far beyond the range of previous weapons. The weakness was that without extraordinary training and talent on the part of the soldier, firearms are quite inaccurate. For a soldier under the pressure of combat, loading and effectively aiming his weapon — particularly with muzzle-loaded firearms — was not an easy task.
To compensate for the inaccuracy of firearms, larger forces could all fire at the same time. Simultaneous firing increased the probability of inflicting casualties on the enemy, and simultaneity, choreographed as it was in multiple lines of troops — with some firing, some waiting and some reloading — maintained near-continuous fire. The solution on the other side was more soldiers pouring more fire on their enemy. Thus, the inaccuracy of a deadly weapon required ever-larger armies.
It also required increasing innovations in weaponry. Firearms evolved from muzzleloaders to breechloaders, then those able to hold clips of multiple rounds and finally the machine gun, which compensated for its own inaccuracy per shot by saturating the horizon with bullets. It was said that in World War I it required 10,000 bullets to kill one soldier. I have no idea where this calculation came from, but it was true in essence. Given the inaccuracy of most riflemen, masses of them were needed. The machine gun made riflemen far more effective.
The approach to warfare that made it less efficient is at the heart of the real issue leading to Hiroshima. Armies surged in size and had to be equipped. Rifles and machine guns were not the work of master smiths but had to be mass-produced in factories, as did a wide range of products needed to support multimillion-man armies. These factories were the key enablers of war. Killing one solder eliminated one rifle, but destroying a factory eliminated the combat power of large numbers of soldiers. Therefore, destroying factories mass-producing the means of war was the most efficient counter to the massed armies made necessary by inaccurate weapons. These factories typically were in cities. In order to function, they had to have efficient transportation links with other factories manufacturing precursor parts, and thus tended to be located near other factories, transportation hubs, and their workers and the systems that employees needed to live and work — houses, grocery stores, schools and so on.
Master military strategist Carl von Clausewitz argued that the key to war was to attack the center of gravity of the enemy’s capacity to wage war. By World War I, the center of gravity was no longer the army but the factories and the workers who produced the engines of war. The distinction between soldier and civilian, critical to all modern notions of military morality, dissolved. The ability to wage war disappeared when the factories did. But given the location of factories, by necessity in cities, any attack on these factories would kill not only workers but also their children, and the milkman’s children. This was, by definition, total war — the only war that could be waged in the industrial age.
At the outset of World War I, there was no way to destroy war-critical factories or populations from a distance. But as with most things, a problem found a solution close at hand. Aircraft made their appearance on the European battlefield during World War I — first as observation planes, then as fighters tasked with shooting down observation planes, and then as bombers tasked with destroying targets identified by reconnaissance aircraft.
Targeting the Industrial Plant
Geopolitically, it was clear that World War I had not solved the fundamental problem of Europe and that another war was inevitable. Among those who believed this were the theorists of air power. Chief among these was Giulio Douhet, an Italian who thought through the reality of war at the time and concluded that the chief solution would be the destruction of the enemy’s war-making capacity. Douhet believed this would best be achieved by aircraft attacking cities en masse and destroying them. Joined in this view by the American Gen. Billy Mitchell and Britain’s Hugh Trenchard, Douhet argued that the key to warfare was to use large numbers of massed bombers to annihilate cities. This would achieve two things: It would destroy the enemy’s industrial plant and trigger a revolt by the public against the government. Because both sides would have massed bombers, the key to war was to launch attacks greater than the enemy’s potential response by both having a larger air force and destroying the enemy’s ability to produce more aircraft.
The inter-war air strategists were in part shaped by the carnage they saw in protracted trench warfare. Douhet believed that the role of air power was almost purely offensive, requiring rapid and destructive attacks against first the opposing forces’ aircraft and then against civilian industrial and commercial centers. Trenchard, like Douhet, saw air power as a strategic and valuable force. Where Trenchard differed from his Italian contemporary was in considering ground forces still important and suggesting joint ground and air operations against enemy airfields. Early American air theorists, including Mitchell and the Army Air Corps Tactical School, viewed the role of strategic bombing as targeted against the war-making capacity of the enemy, rather than against the enemy morale, as Douhet and some European counterparts considered. Mitchell saw attacks on industry, communications and transportation as the real objectives of strategic air power and saw the armies in the field as false objectives.
Douhet implicitly recognized the weakness of aircraft, which was the same as the weakness of rifles: They were extremely imprecise. In 1940, when the British began launching attacks on Germany, the imprecision of the bomber was so great that German intelligence could not figure out what they were trying to bomb. Only massing bombers and destroying cities would work.
The Germans used this dual strategy in the Battle of Britain. They failed both because of lack of sufficient weapons and an air force not designed for strategic bombardment (which is what attacks on cities were called) but for tactical support for ground warfare. The British adopted nighttime area bombardment, making no secret that their goal was the destruction of cities to suppress production and generate political opposition.