Strategic Bombing

1. Lead

Strategic bombing is the use of aircraft to attack an enemy’s industry, transport, cities, and morale, rather than its armies in the field, and it was one of the most important and most controversial tactics of the Second World War.

The idea, developed in the interwar years by theorists such as Giulio Douhet in Italy, Hugh Trenchard in Britain, and Billy Mitchell in the United States, was that bombers could win wars by destroying the factories, oil refineries, railways, and cities that supported an enemy’s war effort, and by breaking the will of its people.

In the Second World War, strategic bombing was carried out on a massive scale by the Royal Air Force’s Bomber Command, under Air Chief Marshal Arthur Harris, and by the United States Army Air Forces, under Generals Carl Spaatz and Curtis LeMay. British bombers attacked German cities at night, American bombers attacked German industry by day, and American bombers later attacked Japanese cities with incendiary bombs.

The campaigns killed hundreds of thousands of civilians, destroyed many of Europe’s and Japan’s cities, and remain the subject of intense moral and historical debate. Strategic bombing did damage German and Japanese industry, and it forced the enemy to divert resources to air defence, but it did not, by itself, win the war, and its effectiveness and its morality continue to be argued about today.

2. Key Facts

Field	Value
Period	1939–1945 (main campaigns 1940–1945)
Main users	RAF Bomber Command; US Eighth Air Force; US Twentieth Air Force
Main targets	German industry, oil, transport, cities; Japanese cities and industry
Key theorists	Giulio Douhet; Hugh Trenchard; Billy Mitchell
Key commanders	Arthur Harris (RAF); Carl Spaatz and Curtis LeMay (USAAF)
German civilian deaths from bombing	About 350,000–500,000 (estimates vary)
Japanese civilian deaths from bombing	About 300,000–500,000, including atomic bombings (estimates vary)
Dresden deaths	About 22,700–25,000 (historical commission, 2010)
Hamburg deaths	About 37,000–45,000 in Operation Gomorrah, July 1943 (estimates vary)
Tokyo firebombing deaths	About 80,000–100,000 on 9–10 March 1945 (estimates vary)

3. Background and Origins

The Theorists of Air Power

The theory of strategic bombing was developed in the years after the First World War, when aircraft had been used for the first time to bomb cities, notably by German Zeppelins and Gotha bombers over London. The Italian general Giulio Douhet, in his book The Command of the Air (1921), argued that future wars would be won by bombing enemy cities, destroying their industry and breaking the morale of their people, and that armies and navies would become secondary.

The British airman Hugh Trenchard, who became the first chief of the Royal Air Force, shared Douhet’s belief in the power of bombing, and he argued that the RAF should be an independent service, capable of attacking the enemy’s heartland.

In the United States, Brigadier General Billy Mitchell argued for an independent air force and for the use of bombers to sink battleships and to attack enemy industry, and he was court-martialled in 1925 for his outspoken views. These theorists were influential, but their predictions were exaggerated: they believed that bombing would cause panic and revolution, and that wars would be short, but in practice, bombing made peoples more determined, and wars lasted for years.

The Interwar Debate and the Limits of Bombing

The interwar debate about strategic bombing was shaped by the fear of air attack, which was widespread in Britain and in Europe in the 1930s, when it was believed that a future war would begin with massive bombing raids on London, Paris, and Berlin, killing hundreds of thousands of people in a few days.

The British government built air-raid shelters and planned for evacuation, and the fear of the bomber influenced British policy, notably the policy of appeasement, which was partly motivated by the fear that Britain could not defend itself against German bombers.

In practice, the bombers of the 1930s were not as powerful as the theorists had claimed, and the defences — fighter aircraft, anti-aircraft guns, and radar — were more effective than expected. The Battle of Britain in 1940 showed that a well-organised air defence could defeat a bombing campaign, and the Blitz on London, though it killed about 40,000 civilians, did not break British morale.

The interwar theorists had overestimated the power of the bomber and underestimated the resilience of civilian populations, a lesson that would be repeated in Germany and Japan.

The Blitz and the German Bombing of Britain

The German bombing of Britain, known as the Blitz, began in September 1940, after the Luftwaffe had failed to defeat the Royal Air Force in the Battle of Britain, and it lasted until May 1941. The Luftwaffe bombed London and other British cities, including Coventry, Birmingham, Liverpool, and Bristol, killing about 40,000 civilians and destroying many homes and factories.

The Blitz was intended to break British morale and to force Britain to sue for peace, but it had the opposite effect, making the British people more determined to resist. The Blitz also showed the limits of strategic bombing: the German bombers, which were mostly medium bombers, could not carry enough bombs to destroy a city, and the British air defences, including fighters, anti-aircraft guns, and radar, shot down many of the attackers.

The Blitz was a failure as a strategic campaign, but it convinced the British that bombing could be a powerful weapon, and it led to the decision to build a large bomber force that would take the war to Germany. The experience of being bombed also shaped British attitudes to the bombing of German cities, making it easier to justify in the years that followed.

4. Core Principles

Attacking Industry and Morale

The core principle of strategic bombing was that an enemy’s war effort depended on its industry, its transport, and the morale of its people, and that by attacking those targets, a bomber force could cripple the enemy without having to defeat its armies in the field.

The targets chosen by the British and American bomber forces included aircraft factories, ball-bearing plants, oil refineries, railway yards, and, increasingly, the cities themselves, where the workers who made the weapons lived. The British, under Harris, believed that the most effective way to destroy German industry was to destroy the cities where the workers lived, a policy known as area bombing, while the Americans believed in precision bombing, attacking specific factories and installations by day.

Both approaches were based on the same principle: that bombing could destroy the enemy’s ability to make war, and that it could do so more quickly and more cheaply than a land invasion. In practice, the principle was only partly true, because German and Japanese industry proved resilient, and because the workers continued to work even after their homes had been destroyed.

Area Bombing Versus Precision Bombing

The difference between area bombing and precision bombing was one of the central debates of the strategic bombing campaign, and it reflected the different capabilities and doctrines of the RAF and the USAAF. The RAF, which bombed at night, could not aim accurately at individual factories, and it therefore adopted area bombing, dropping large numbers of bombs on a city in the hope of destroying its industry and its housing.

The USAAF, which bombed by day, using the Norden bombsight, believed that it could hit individual targets accurately, and it therefore adopted precision bombing, attacking oil refineries, aircraft factories, and railway yards. In practice, precision bombing was less accurate than the Americans claimed, and many bombs missed their targets and fell on residential areas, while area bombing, though it destroyed cities, did not destroy German industry as quickly as Harris had hoped.

The debate between area and precision bombing continues among historians, with some arguing that precision bombing was more effective and more moral, and others arguing that area bombing, though brutal, was the only way to damage German industry given the technology of the time.

The Bomber as a Strategic Weapon

The bomber as a strategic weapon was based on the idea that aircraft could fly over armies and navies, and attack the enemy’s heartland directly, a concept that was new in the Second World War. The bomber was seen as a weapon that could win wars on its own, without the need for a land invasion, and that belief motivated the building of large bomber forces in Britain and the United States.

The British built the Lancaster, a four-engined heavy bomber that could carry a large bomb load, and the Americans built the B-17 Flying Fortress and the B-24 Liberator, which could fly in daylight and defend themselves with machine guns. The bombers were supported by long-range fighters, notably the P-51 Mustang, which could escort them to Germany and back, and by electronic aids, such as radar and radio navigation, which allowed them to find their targets at night.

The bomber, however, was vulnerable to fighters and to anti-aircraft guns, and the losses among bomber crews were among the highest of any service in the war, with about 55,000 RAF Bomber Command airmen killed, a casualty rate of about 44 per cent.

5. How It Worked in Practice

RAF Bomber Command and the Night Offensive

RAF Bomber Command, under Air Chief Marshal Arthur Harris from February 1942, carried out the night bombing offensive against Germany, attacking cities such as Cologne, Hamburg, Berlin, and Dresden. The raids were carried out by hundreds of bombers, flying in a stream, dropping incendiary and high-explosive bombs on the target city, and returning to Britain before dawn.

The raids were supported by electronic countermeasures, such as Window, strips of aluminium foil that confused German radar, and by Pathfinder aircraft, which marked the target with flares. The night offensive was costly, with many bombers shot down by German night fighters and by anti-aircraft guns, but it was also destructive, and it forced Germany to divert large numbers of fighters, guns, and men to air defence, resources that could otherwise have been used on the Eastern Front.

The most destructive raid of the night offensive was Operation Gomorrah, the bombing of Hamburg in July 1943, which created a firestorm that killed about 37,000–45,000 people and destroyed much of the city.

The Firestorm at Hamburg

The firestorm at Hamburg in July 1943 was one of the most terrible events of the strategic bombing campaign, and it showed the destructive power of incendiary bombing. On the night of 27–28 July, RAF bombers dropped thousands of incendiary bombs on Hamburg, starting fires that merged into a single firestorm, with temperatures reaching 800 degrees Celsius, winds of hurricane force, and a column of smoke that rose several kilometres into the sky.

The firestorm destroyed about 8 square kilometres of the city, killed about 37,000–45,000 people, according to most estimates, and left about a million people homeless. The firestorm was not planned as such, but it was the result of the combination of dry weather, the density of the bombing, and the wooden buildings of the old city.

The Hamburg firestorm shocked the German leadership, and it led to the evacuation of many German cities, but it did not break German morale, and the city was rebuilt after the war. The firestorm remains a symbol of the horror of strategic bombing, and of the suffering that it caused to civilians.

The US Eighth Air Force and Daylight Bombing

The US Eighth Air Force, under Generals Carl Spaatz and James Doolittle, carried out the daylight bombing offensive against Germany, attacking oil refineries, aircraft factories, and railway yards by day, in the belief that precision bombing could destroy German industry.

The daylight raids were carried out by formations of B-17 and B-24 bombers, flying in tight boxes and defending themselves with machine guns, and they were initially flown without fighter escort, because no American fighter had the range to reach Germany and back.

The losses were heavy, notably at Schweinfurt in October 1943, when the Americans lost 60 bombers in a single raid, and the daylight offensive was suspended until the P-51 Mustang, a long-range fighter, became available in 1944. With Mustang escort, the American bombers were able to attack Germany in daylight with fewer losses, and they destroyed the German oil industry and the Luftwaffe, shooting down many German fighters and killing many of their pilots.

The daylight offensive was a key part of the Allied victory, because it destroyed the fuel that the German Army and Air Force needed to fight, and it forced the Luftwaffe to defend Germany, rather than supporting the army in the field.

6. Key Examples

Dresden, February 1945

The bombing of Dresden on 13–15 February 1945 was one of the most controversial raids of the war, and it has been debated ever since. Dresden, a city in eastern Germany known for its baroque architecture and its cultural heritage, was bombed by RAF Bomber Command on the night of 13 February, and by the USAAF on the following days, in a series of raids that created a firestorm and destroyed much of the city centre.

The number of people killed has been the subject of much debate, with Nazi propaganda claiming 200,000 or more, and with later historians giving much lower figures. A historical commission in Dresden in 2010, after years of research, concluded that about 22,700–25,000 people were killed, a figure that is now generally accepted by historians.

The bombing of Dresden was carried out at a time when the war was almost over, and when the city was crowded with refugees fleeing the Soviet advance, and its necessity has been questioned. The raid was intended to disrupt German transport and to support the Soviet advance, but its military value was limited, and its destruction of a cultural city has made it a symbol of the moral problems of strategic bombing.

The Debate Over Dresden

The debate over Dresden has continued for decades, with some arguing that the bombing was a war crime, and others arguing that it was a legitimate military operation. The high figures claimed by Nazi propaganda, of 200,000 or 500,000 dead, were false, and were used to discredit the Allies, but the true figure of about 22,700–25,000 is still a large number, and the bombing of a city with little military industry, at a late stage of the war, has been criticised.

The British and American commanders who ordered the raid argued that Dresden was a transport hub, that it contained factories, and that its bombing would help the Soviets, who had asked for it. Historians have generally concluded that Dresden was not a unique atrocity, but part of a wider pattern of area bombing, and that its fame is due more to its cultural significance and to Nazi propaganda than to its military importance.

The debate over Dresden remains a reminder that the morality of bombing is complex, and that even a legitimate military aim can cause great suffering.

Tokyo, March 1945

The firebombing of Tokyo on 9–10 March 1945 was the most destructive single air raid of the Second World War, and it killed about 80,000–100,000 people, according to most estimates, more than the atomic bombings of Hiroshima and Nagasaki individually.

The raid was carried out by 279 B-29 bombers of the US Twentieth Air Force, under General Curtis LeMay, which dropped incendiary bombs on the densely populated, wooden districts of Tokyo, creating a firestorm that destroyed about 40 square kilometres of the city. The raid was part of a wider campaign of firebombing Japanese cities, which LeMay had begun after concluding that precision bombing was ineffective against Japan’s dispersed industry.

The firebombing campaign destroyed many Japanese cities, killed hundreds of thousands of civilians, and left millions homeless, and it was a key factor in Japan’s decision to surrender, though the atomic bombings and the Soviet invasion of Manchuria were also important. The Tokyo raid, like Dresden, remains controversial, and it is remembered as one of the most terrible events of the war in the Pacific.

7. Strengths

Forcing the Enemy to Divert Resources

One of the main strengths of strategic bombing was that it forced the enemy to divert large resources to air defence, resources that could otherwise have been used on the battlefield. Germany, for example, had to deploy about a million men, thousands of guns, and many of its best fighter aircraft to defend its cities, rather than sending them to the Eastern Front or to Normandy.

The German anti-aircraft guns, the famous 88mm guns, were used in large numbers for air defence, rather than as anti-tank guns, and the Luftwaffe, which had once been an offensive force, became a defensive force, fighting over Germany rather than over the battlefield. Japan, too, had to divert resources to air defence, though its defences were weaker than Germany’s.

The diversion of resources was a significant strategic effect, even if the bombing did not destroy German industry as quickly as its advocates had hoped, and it was one of the main arguments in favour of the bombing campaign.

Damaging Oil and Transport

Another strength of strategic bombing was its effect on German oil and transport, which were attacked by the American daylight bombers in 1944–1945 and which were severely damaged. The bombing of oil refineries, notably at Ploesti in Romania and in Germany itself, reduced German oil production to a fraction of its former level, leaving the German Army and Air Force short of fuel, and making it difficult for them to move and to fight.

The bombing of railway yards and bridges, notably in the months before D-Day, disrupted German transport, making it difficult for the Germans to move reinforcements to Normandy and slowing their response to the invasion. The attack on oil and transport, which was a form of precision bombing, was more effective than the attack on cities, and it is now generally regarded as the most successful part of the strategic bombing campaign.

The damage to oil and transport contributed directly to the German defeat, by depriving the German armed forces of the fuel and the mobility they needed.

Supporting the Land Campaign

Strategic bombing also supported the land campaign, by preparing the way for the invasion of Normandy and by weakening the German defences in France. In the months before D-Day, Allied bombers attacked railway yards, bridges, and airfields in northern France, in a campaign known as the Transportation Plan, which isolated Normandy and made it difficult for the Germans to bring up reinforcements.

The bombing also attacked German radar stations and coastal defences, and it provided air support for the landings themselves. The success of D-Day was partly due to the bombing campaign, which had weakened the Germans before the invasion began. The bombing of Japan, similarly, prepared the way for the planned invasion of Japan, though the invasion was never carried out because Japan surrendered after the atomic bombings.

Strategic bombing, therefore, was not a substitute for a land invasion, but a preparation for it, and its greatest strength was in supporting the armies in the field.

8. Weaknesses and Limitations

Inaccuracy and High Losses

The main weakness of strategic bombing was its inaccuracy, especially at night, when RAF bombers often missed their targets by kilometres, dropping their bombs on residential areas rather than on factories. The American daylight bombers, though more accurate, also missed many of their targets, and their losses were heavy, especially before long-range fighter escort became available.

The losses among bomber crews were among the highest of any service, with about 55,000 RAF airmen killed and about 26,000 American airmen killed in Europe, and the cost in aircraft and in trained crews was enormous. The inaccuracy and the losses meant that strategic bombing was a very expensive way to damage the enemy, and that it took a long time to achieve results.

The campaign also required a huge industrial effort to build the bombers, to train the crews, and to supply them with fuel and bombs, an effort that could have been used for other purposes, such as building tanks or landing craft.

Failure to Break Morale

Another weakness of strategic bombing was its failure to break civilian morale, which was one of its main aims. The theorists had predicted that bombing would cause panic and revolution, but in practice, the peoples of Britain, Germany, and Japan became more determined under bombing, not less.

The British endured the Blitz, the Germans endured the bombing of their cities, and the Japanese endured the firebombing of theirs, and in each case, morale did not collapse. The bombing did cause suffering, fear, and hardship, but it did not lead to a demand for peace, and in Germany and Japan, it may even have strengthened support for the regime, by making the people feel that they were victims of the enemy.

The failure to break morale was a major disappointment for the advocates of strategic bombing, and it showed that civilian populations are more resilient than the theorists had believed. Workers returned to damaged factories, families sheltered together during raids, and local communities organised relief, food, and medical care, showing a resilience that surprised both their own leaders and the men who ordered the bombing.

The Moral Cost

The moral cost of strategic bombing was its greatest weakness, because it involved the deliberate killing of civilians, including women and children, on a large scale. The bombing of German and Japanese cities killed hundreds of thousands of civilians, destroyed cultural heritage, and left millions homeless, and it has been condemned as a war crime by some historians and by many of those who lived through it.

The Allied leaders who ordered the bombing, notably Harris and LeMay, defended it as necessary to win the war, and argued that the Germans and Japanese had started the bombing of civilians, but the moral debate continues. The bombing of Dresden and Tokyo, in particular, has been criticised as unnecessary and disproportionate, and the question of whether strategic bombing was morally justified remains one of the most debated issues in the history of the Second World War.

The moral cost of bombing is a reminder that even a tactic that is militarily effective can have a high human price.

9. Evolution and Legacy

From Area Bombing to Precision Weapons

The legacy of strategic bombing includes its evolution from the area bombing of the Second World War to the precision bombing of today, in which guided weapons can hit individual buildings with great accuracy. The inaccuracy of Second World War bombing, which led to the destruction of whole cities, has been replaced by weapons that can destroy a single target with minimal collateral damage, and the doctrine of strategic bombing has changed accordingly.

Modern air forces no longer aim to destroy cities, but to attack specific military and industrial targets, using precision-guided munitions, stealth aircraft, and drones. The evolution of bombing has been driven by technology, but also by the moral lessons of the Second World War, which showed that the indiscriminate bombing of civilians was both ineffective and morally troubling.

The legacy of strategic bombing, therefore, is not only a military one, but also a moral one, and it has shaped the way that air power is used today.

The Atomic Bomb and the End of the War

The atomic bombings of Hiroshima and Nagasaki in August 1945 were the culmination of the strategic bombing campaign, and they marked a new stage in the history of warfare. The atomic bombs, which were dropped by B-29 bombers, killed about 100,000–200,000 people, according to most estimates, and they forced Japan to surrender, ending the Second World War.

The atomic bombings were a form of strategic bombing, in that they attacked cities to break the enemy’s will, but they did so with a single weapon, rather than with hundreds of bombers. The legacy of the atomic bombings is the nuclear age, in which strategic bombing became a matter of deterrence, rather than of actual use, and in which the threat of bombing was used to prevent war, rather than to win it.

The strategic bombing of the Second World War, therefore, led directly to the nuclear strategy of the Cold War, and its legacy is still with us today.

The Historical Debate

The historical debate about strategic bombing continues, with historians arguing about its effectiveness, its morality, and its contribution to the Allied victory. Some argue that bombing was decisive, that it destroyed German industry and forced the enemy to divert resources, and that it shortened the war.

Others argue that bombing was ineffective, that German industry proved resilient, that it did not break morale, and that the resources spent on bombers could have been better used elsewhere. The truth is probably in the middle: bombing did damage the enemy, but it did not win the war on its own, and its contribution was less than its advocates claimed.

The debate about strategic bombing is a reminder that military history is not only about what happened, but about how we judge it, and that the bombing campaign, with its mix of success and failure, of courage and suffering, will continue to be debated for as long as war is studied.

10. Comparison with Alternatives

Bombing Versus Invasion

Strategic bombing was often presented as an alternative to a land invasion, a way to win the war without the heavy casualties of a ground campaign, but in practice, bombing did not replace invasion, and the Allies still had to invade Normandy and to fight their way across Europe.

The bombing campaign, though it damaged Germany, did not force it to surrender, and it was only when Allied armies entered Germany that the war ended. The comparison between bombing and invasion shows that bombing, on its own, is not enough to win a war against a determined enemy, and that it must be combined with land and sea power to be effective.

The Allies learned this lesson in the Second World War, and they applied it in later wars, where bombing has been used to support ground forces, rather than to replace them. The alternative to bombing, therefore, was not to do nothing, but to use bombing as part of a combined campaign, in which air, land, and sea forces work together.

Bombing Versus Blockade and Other Strategies

Another alternative to strategic bombing was blockade, the use of naval power to cut off the enemy’s supplies, and the Allies used both bombing and blockade against Germany and Japan. The blockade of Germany, by the Royal Navy, and of Japan, by American submarines, was effective in depriving the enemy of food, oil, and raw materials, and it contributed to the Allied victory.

The comparison between bombing and blockade shows that both were forms of economic warfare, aimed at destroying the enemy’s ability to make war, and that both were more effective when used together. The bombing of oil refineries, for example, was more effective when combined with the submarine blockade of oil imports, and the bombing of transport was more effective when combined with the mining of harbours.

The lesson is that no single tactic wins a war on its own, and that strategic bombing, like blockade, was most effective as part of a wider strategy.

Tactical Air Support Versus Strategic Bombing

Tactical air support, the use of aircraft to support armies in the field, was an alternative to strategic bombing, and it was often more effective, because it directly helped the troops on the ground. The Allies used tactical air support extensively in Normandy, in France, and in Germany, with fighter-bombers attacking German tanks, artillery, and troops, and with transport aircraft supplying the advancing armies.

Tactical air support was more accurate than strategic bombing, because the targets were closer and easier to see, and it had a more immediate effect on the battle. The comparison between tactical and strategic bombing shows that the most effective use of air power is often the most direct one, supporting the armies in the field, rather than attacking distant cities.

The strategic bombing campaign, though it had its successes, was less effective than tactical air support in the final year of the war, when the Allied armies were advancing rapidly and needed close support.

Frequently Asked Questions

What is strategic bombing?
Strategic bombing is the use of aircraft to attack an enemy’s industry, transport, cities, and morale, rather than its armies in the field, with the aim of crippling its ability to make war.

Who carried out strategic bombing in the Second World War?
RAF Bomber Command under Arthur Harris bombed Germany at night, the US Eighth Air Force bombed Germany by day, and the US Twentieth Air Force firebombed Japanese cities and dropped the atomic bombs.

How many people died in the bombing of Dresden?
A historical commission in Dresden in 2010 concluded that about 22,700–25,000 people were killed. Nazi propaganda claims of 200,000 or more are false.

How many people died in the Tokyo firebombing?
About 80,000–100,000 people were killed on 9–10 March 1945, according to most estimates, making it the most destructive single air raid of the war.

Did strategic bombing win the war?
No, not on its own. It damaged German and Japanese industry and forced the enemy to divert resources to defence, but the war was won by the combined efforts of land, sea, and air forces.

Was strategic bombing morally justified?
This remains debated. Its defenders argue it was necessary to defeat Germany and Japan, while its critics argue that the deliberate bombing of civilians was disproportionate and ineffective in breaking morale.

Related articles

• Encirclement
• Operation Fortitude
• Blitzkrieg

Sources

• The Imperial War Museum, Bomber Command collection
• Richard Overy, The Bombing War: Europe 1939–1945 (2013)
• Max Hastings, Bomber Command (1979)
• The Dresden Historical Commission, Report (2010)
• The US Air Force Historical Research Agency, Strategic Bombing Survey
• Giulio Douhet, The Command of the Air (1921)