The British had chosen not to bomb Vemork because Lief Tronstad, the physical chemist attached to Norwegian intelligence in London, had warned that hitting the hydrochemical facility's liquid-ammonia storage tanks would almost certainly kill large numbers of Norwegian workers. But the British had in any case long since abandoned precision bombing.
Winston Churchill had declared himself strongly in favor of strategic air attack early in the war, speaking even of extermination. In July 1940, in the desperate time after the debacle of Dunkirk and at the beginning of the Battle of Britain, Churchill had written his Minister of Aircraft Production to that effect: “But when I look round to see how we can win the war I see that there is only one sure path… and that is absolutely devastating, exterminating attack by very heavy bombers from this country upon the Nazi homeland. We must be able to overwhelm them by this means, without which I do not see a way through.”
The slide from precision bombing attacks on industry to general attacks on cities followed less from political decisions than from inadequate technology. Bomber Command had attempted long-distance daylight precision bombing early in the war but had been unable to defend its aircraft against German fighters and flak so far from home. It therefore switched to night bombing, which reduced losses but severely impaired accuracy. If it was logical to bomb factories and other strategic targets to reduce the enemy's ability to wage war, it began to seem equally logical to bomb the blocks of workers' housing that surrounded those targets; the workers, after all, made the factories run. Sir Arthur Harris, who became chief of Bomber Command in early 1942, notes in his war memoirs of this transitional period in the summer of 1941 that “the targets chosen were in congested industrial areas and were carefully picked so that bombs which overshot or undershot the actual railway centers under attack [in this instance] should fall on these areas, thereby affecting morale. This programme amounted to a halfway stage between area and precision bombing.” “Morale” is here and elsewhere in the literature of air power a euphemism for the bombing of civilians. Another sign of halfway status at this stage was permission to dump bombs before exiting Germany if crews had missed their targets.
Churchill says he authorized a study of bombing accuracy at Frederick Lindemann's suggestion which discovered in the summer of 1941 “that although Bomber Command believed they had found the target, two-thirds of crews actually failed to strike within five miles of it… Unless we could improve on this there did not seem much use in continued night bombing.” In November the government ordered its bomber arm to reduce operations over Germany.
To reduce strategic bombing operations was to admit failure in both theory and practice, and it was to do so at a time when the USSR was fully engaged with the German armies on the Eastern Front and Joseph Stalin was demanding the Allies open a second front in the West. Neither Britain nor the United States was nearly prepared yet to invade Europe on the ground, but both nations might offer such aid as air attack could bring. Aiding the Soviet Union was a political justification for continuing some kind of strategic bombing campaign, though it hardly placated Stalin. Headlines proclaiming almost daily bombing raids also helped keep the home front happy when the ground war stalled.
Yet Allied politics and domestic propaganda could not have been the primary reasons for the drift from precision to area bombing, because U.S. air forces beginning to arrive in Britain in 1942 planned and carried out precision daylight bombing, though not often effectively, until much later in the war. Rather, Bomber Command switched programs in order to justify its continued existence as a service with a mission separate from Army and Navy tactical support, cutting theory to fit the facts. It found an ally in the newly ennobled Lindemann, Lord Cherwell, who calculated in March 1942 that bombing might destroy the housing of a third of the German population within a year if sufficiently pursued against industrial urban areas. Patrick Blackett and Henry Tizard thought Cherwell's estimate far too optimistic and dissented vigorously, but Cherwell had the Prime Minister's ear.
Sir Arthur Harris — “Butch,” his staff came to call him, short for “the Butcher” — took over Bomber Command in February and promulgated a new approach to the air war: “It has been decided that the primary objective of your operations should now be focussed on the morale of the enemy civil population and in particular, of the industrial workers.” Harris had witnessed the London Blitz; it convinced him, he writes, that “a bomber offensive of adequate weight and the right kind of bombs would, if continued for long enough, be something that no country in the world could endure.” His argument was valid, of course, though what “the right kind of bombs” might be would require the work of the Manhattan Project to reveal. Hitler's terror bombing taught Britain not terror but forceful imitation. Harris certainly despised the Germans for starting and perpetuating two world wars. But he seems to have thought less about killing civilians than about solving the problem of making Bomber Command a measurably effective force. If night bombing and area bombing were the only tactics that paid a reasonable return in destruction at a reasonable price in lost aircraft and aircrew lives, then he would dedicate Bomber Command to perfecting those tactics and measure success not in factories rendered inoperative but in acres of cities flattened. Which is to say, area bombing was invented to give bombers targets they could hit.
An incendiary attack on the old Baltic port of Liibeck in March burned much of the town and produced four- figure casualties for the first time in the bombing campaign. On May 20, to demonstrate Bomber Command's effectiveness at a time of public debate, Harris mustered every aircraft he could find — hundreds of two-engine bombers of light payload and even training planes — to launch a thousand-bomber raid on Cologne. For that successful assault he organized what came to be called a bomber “stream,” the aircraft flying in massed continuous formations to overwhelm defenses rather than in small and vulnerable packets as before, and destroyed some eight square miles of the ancient city on the Rhine with 1,400 tons of bombs, two-thirds of them incendiary. Finally, in August, encouraged by Cherwell, Bomber Command deployed a Pathfinder force: skilled advance crews that marked targets with colored flares so that less experienced pilots following in the lethal stream could more easily find their aiming points.
No fleet of bombers could yet accurately deliver enough high explosives to raze a city. The Liibeck bombing had been planned to test the theory that area bombing worked best by starting fires. If the bombloads were incendiary, then the massed aircraft might combine their destructiveness, wind and weather cooperating, rather than disperse it on isolated targets. The theory worked at Liibeck and again at Cologne and because it worked it won adoption. At the end of 1942 the British Chiefs of Staff called for “the progressive destruction and dislocation of the enemy's war industrial and economic system, and the undermining of his morale to a point where his capacity for armed resistance is fatally weakened.” Churchill and Roosevelt affirmed the British plan for an aerial war of attrition in a directive issued at the conclusion of the Casablanca Conference in late January 1943.
On May 27, 1943, as work began at Los Alamos following the April conferences, Bomber Command ordered Hamburg attacked. Its
INFORMATION
The importance of Hamburg, the second largest city in Germany with a population of one and a half millions, is well known… The total destruction of this city would achieve immeasurable results in reducing the industrial capacity of the enemy's war machine. This, together with the effect on German morale, which would be felt throughout the country, would play a very important part in shortening and in winning the war.
2. The “Battle of Hamburg” cannot be won in a single night. It is estimated that at least 10,000 tons of
