Friedrich takes little account of the desperate situation of Britain for the first two or three years of the war, unable to hit back at Germany except by air; nor of the connection between the decisions by Churchill and Roose-velt at Casablanca in January 1943 to demand unconditional surrender, to postpone the second front and to step up the strategic air offensive. Friedrich makes the familiar argument that once the mass production of heavy bombers had been decided upon, the offensive had to continue whether or not it was succeeding.

But the Allied bombers were created in response to the threat of the Luftwaffe, which was believed to be building similar fleets. Without the damage to German production and the colossal diversion and waste of resources that the offensive imposed on the Nazi war machine, that threat might have been realized.

Above all, Friedrich never properly considers the actual impact of the bombing offensive on the outcome of the war. Yet that impact is hard to overestimate.

In 1942 the Germans could still mount their thousand-bomber raid on Stalingrad.

By 1943, the Luftwaffe had lost control of the air on the Eastern Front because

70 per cent of its fighters were needed to defend the Reich. The firebombing of Hamburg was indeed horrific, but it caused even men like Albert Speer and Field Marshal Milch to contemplate defeat. Indeed, Speer concluded that the bombing offensive was "the greatest lost battle on the German side". The German war effort was undermined not only by actual death and destruction, but by the progressive exhaustion and defeatism of the population: absenteeism rose, some 2 million men were devoted to air defence, a third of all artillery production was anti-aircraft guns, and so on. Once the bombing offensive had broken the Luftwaffe in early 1944, control of the air transformed the invasion of Europe from a suicidal adventure into a practical possibility. Friedrich's book offers no reason to dissent from Richard Overy's judgement that "the air offensive was one of the decisive elements in Allied victory". Even from a German standpoint, that is surely the clinching moral argument in its favour.

Friedrich's book illustrates the way in which the boundaries of acceptable discourse about the Nazi past have been steadily extended in Schroder's Germany.

The reconciliation between victors and vanquished after 1945 depended on a tacit understanding to keep silent about the past. Adenauer's Germany may have been in denial, but what was the alternative? A national nervous breakdown? Today, the moral imperative is not to repress the past, but on the contrary to denounce such repression, even if what turns out to have been repressed is a mixture of self-pity and resentment against former victims or enemies.

The eminent liberal novelist Martin Walser claimed a few years ago that German guilt about the Holocaust was being "instrumentalized"; more recently, he risked more direct accusations of anti-Semitism with his thinly disguised fictional portrait of the Jewish critic Marcel Reich-Ranicki. An even more respected figure, the Nobel laureate Gunter Grass, recently chose to evoke the sinking of the Wilhelm Gustloff, a ship full of German refugees fleeing from the Russians which also makes an appearance in Friedrich's book. Now another festering sore has been reopened: the destruction of the German cities by Anglo-American bombers. With perfect timing, Friedrich aimed his bombshell of a book at the ageing edifice of the Atlantic Alliance, just as the dam was weakening. Germany has now been inundated with a flood of anti-Americanism, but it is too soon to say what else of the post-war settlement has been swept away.

The taboo on mutual recrimination certainly has.