Thomas Powers, Heisenberg's War: the secret history of the German bomb (Jonathan Cape, £20)

"Politics is prior to the vagaries of science" - Green Gartside

The German bomb was the dog that didn't bark in the Second World War. What was to become the Manhattan Project was initially approved by Roosevelt "to see that the Nazis don't blow us up". Many of the world's leading nuclear physicists were German; some had fled the country, but many had remained. Yet there was no German bomb: US forces entering Strasbourg in 1944 discovered that German physicists were still "debating the fundamentals of reactor design". The question is why.

Powers gives us two stories and one answer. There is the story of the German bomb programme itself, and of its passage from desk to desk in the bureaucratic nightmare that was the Nazi state: this, despite the book's subtitle, is curiously scanted and unfocussed. By contrast the story of what the British and US governments knew about the programme and what they did about it is told with energy and precision, illuminating part of the war's covert underside. There is the high drama of a successful, though ineffectual, commando raid on a heavy water plant in occupied Norway; the tragicomedy of "Operation Shark", a bungled attempt by the OSS - forerunner of the CIA - to bring nuclear physicists out of occupied Italy; the black farce of an OSS agent sitting through a lecture on "S-matrix" theory with a gun in his pocket, prepared to shoot the lecturer if he made any reference to bomb physics. The predominant tone of these episodes is of inefficiency, wasted effort and absurdity, but then covert operations were ever thus.

Neither the history of the German atomic programme nor the Allies' successive, fumbling attempts to understand or prevent it furnishes Powers' answer. That lies in one man: Werner Heisenberg. The co-founder of quantum physics with Niels Bohr, Heisenberg was the greatest of all the physicists who had made their peace with Hitler: "the most dangerous possible German in the field because of his brain power", in the words of a British physicist. (These words were taken seriously in OSS circles - hence the lecture-theatre operation). If anyone could secure funding for a bomb programme it was Heisenberg; if anyone was to lead a bomb programme and make it succeed, Heisenberg was the man. And if Heisenberg didn't want to build the bomb? This is not a hypothetical question: in the words of a message sent to US physicists in 1941, "We are trying here hard, including Heisenberg, to hinder the idea of making a bomb. But the pressure from above... Heisenberg will not be able to withstand longer the pressure from the government".

Powers argues that this was to underestimate Heisenberg: that Heisenberg withstood the government to the point of undermining the German bomb programme. Every step of the way, Heisenberg stressed the risks and difficulties of the project; asked point blank to set a timescale, Heisenberg denied that a bomb could be built in time to assist the war effort. Heisenberg even visited Bohr in occupied Denmark in 1941, knowing that Bohr had contacts with the Allies, and spoke openly about his work on the bomb programme before suggesting a worldwide physicists' agreement not to work on nuclear weaponry. Far from being "the most dangerous possible German", Heisenberg was the Allies' biggest asset; if anything, Heisenberg's opposition to nuclear weapons research makes him contrast favourably with the physicists of the Manhattan Project.

There are three main propositions here. Firstly, Heisenberg was an anti-fascist, unafraid to give away classified information to the Allies. Secondly, although Heisenberg accepted official positions under the Nazis, he obstructed atomic weapons research as effectively as if he had offered the regime open resistance, if not more so. Lastly, Heisenberg's resistance was crucial in preventing a serious German bomb programme, which otherwise could have parallelled the Manhattan Project and won the war for Hitler. A book could be written demolishing this argument; unfortunately Powers' book is dedicated to stating and re-stating it, often in the teeth of the facts it documents. I believe it is wrong on all counts: Heisenberg's politics, his supposed stand against the bomb programme, the significance of that stand and the feasibility of a German bomb programme under the Nazis.

Powers argues that Heisenberg as a young man "had no politics in the usual sense of the term", and appears to believe that his later anti-Nazism rested on this unworldly base. Yet well into his twenties Heisenberg was a keen member of the Jugendbewegung (Youth Movement), an organisation combining outdoor pursuits with a philosophy made up of elitism, anti-intellectualism and ethnic nationalism. At the age of 17 Heisenberg served in a Munich citizens' militia, assisting the Freikorps forces which violently suppressed the 1919 Communist government of Bavaria. According to one source the Munich rising was organised by the Thule Society, a mystical nationalist organisation with links to the early Nazi Party; Thule associates included Rudolf Hess, who also fought in Munich as a member of the Freikorps.

Far from having "no politics", Heisenberg had political views which he expressed with remarkable consistency and frankness. When Hitler took power Bohr remarked to his assistant Leon Rosenfeld, "I have just been to see Heisenberg and you should see how happy Heisenberg is. Now we have at least order." (Bohr, who was half-Jewish, revised this opinion subsequently). In 1938 Heisenberg dismissed the possibility of a Nazi-Soviet pact with "No patriotic German would ever consider that option". In the course of his visit to Bohr in 1941 he expressed satisfaction at the subjection of Eastern Europe, arguing that "these countries were not able to govern themselves", and looked forward to Germany defeating Russia; in 1943 he argued that it was Germany's historic mission to defend Europe against Eastern barbarism, and that a German-ruled Europe might be the lesser of two evils. (Powers says only that "There are times when the 'lesser evil' is a defensible choice, but October 1943 was not one of them". Perhaps if it had been the lesser evil...) As late as December 1944, Heisenberg conceded that the war was lost but added that "it would have been so fine if we had won".

Powers explains these remarks and the offence they caused by proposing either tactlessness or the constraints of office on Heisenberg's part, compounded by over-sensitivity on his audience's. A truer reading might be that, while Heisenberg was no Nazi - he was not anti-semitic, for example - he shared much of the Nazi world-view and hoped for a German victory. He believed that the Nazi leadership would not survive the end of the war, using the analogy of muddy water: stir it up and the dirt rises to the top, let it settle and the dirt drops to the bottom. "I'm not a Nazi but a German," he protested in 1944; earlier that year Albert Speer had expressed similar priorities, proclaiming that "we shall continue to do our duty so that our German people will be preserved".

Albert Speer was appointed Minister of Armaments in 1941 and given formal powers to direct the German economy in March 1942. Speer was a technocrat, relatively unburdened by Nazi ideology, and a long-time enthusiast for the Peenemünde rocket programme which culminated in the V-2s; if anyone could initiate a German Manhattan Project he could. However, the Powers interpretation runs, Speer was no match for Heisenberg's delaying tactics. At a conference on nuclear fission organised by the Education Ministry in June 1942, Heisenberg told Speer that an atom bomb would take two years to develop and left the impression that research was still in its first stages; told that Autumn "not to count on anything for three or four years", Speer "scuttled the project". For the rest of the war German research concentrated on the peaceful applications of nuclear fission. If Heisenberg had said a bomb could be built, Speer would have supplied the money and the manpower; Heisenberg said it couldn't be done, and it was not done.

This interpretation misses everything of significance. Firstly, if Heisenberg had genuinely wanted to hinder the German atomic programme he had only to leave Germany. Nuclear physics was initially rejected by the Nazis as "Jewish physics" owing to its origins in the work of Einstein. In 1938 Heisenberg fought a protracted battle with proponents of Newtonian - "Aryan" - physics, ultimately resolved by a personal approach to Himmler. If depriving Germany of the atom bomb was the object, nothing could have been more effective than leaving the field and giving "Aryan physics" a free run. Secondly, although Heisenberg - like many other nuclear physicists - appears to have been genuinely opposed to bomb development, his timescales were not in fact overly pessimistic: in America almost three years elapsed between presidential approval and the christening of the Manhattan Project, another three before the first bomb test. In 1942 no honest physicist could have promised an atom bomb inside two years. Speer might have been willing to hurry the process along by pouring resources into fission research, had there been anything to pour them into: unlike the V-2, the Army's pet project since 1937, fission research in 1942 was still at too early a stage to be funded on an industrial scale. Finally, the reason why the Education Ministry had charge of fission research in 1942 was that the Army had abandoned it the previous year. The bomb had already been rejected for the war effort before Heisenberg's intervention.

In understanding why atomic weapons research was dropped, first by the Army and then by Speer, the timescale is decisive. At the end of 1941 almost all of continental Europe was under Axis control, Britain was blockaded and German armies were advancing into Russia. Victory in Russia seemed assured; all Germany had to do was to reach terms with Britain and the US - then newly at war with Japan - and the era of German-ruled peace anticipated by Heisenberg could begin. Heisenberg's visit to Bohr fits in this context: far from sending a message to nuclear physicists working for the Allies, Heisenberg was canvassing Bohr's co-operation, as a citizen of the German empire, in the post-war development of nuclear power. Under these circumstances it made no sense for the Army to back long-term programmes which might some day lead to new weapons: the old ones were doing the job, after all.

By 1943 the situation had been reversed, in Russia, in Africa and in the air. The pressure of imminent defeat called for the acceleration of existing weapons programmes, such as the V-2, and the introduction of new weapons which could be developed quickly, such as the V-1 flying bombs: once again, for different reasons, atomic weapons research seemed too speculative and too long-term to be worthwhile. Add to this the practical effect of Allied bombings, which in 1943 destroyed the Norwegian plant which was Germany's only source of heavy water, and the German bomb was a non-starter. Speer concluded after the war that "with extreme concentration of all our resources" - including the abandonment of Peenemünde - "we could have had a German atom bomb by 1947".

Even this was probably a hopeful estimate. Paradoxically, "extreme concentration of resources" was not easy in Nazi Germany. Hitler's rule was based on the dispersal of power: from his immediate subordinates to regional party officials, everyone in authority had their own power base, their own interests and the freedom to pursue them. The consequence was that, unlike the ideological mobilisation of the population, the mobilisation of the German economy for war happened piecemeal if at all. After the Army had taken control of the atomic programme in 1940 research was carried out, not in the barracks conditions of the Manhattan Project, but by what was called the Uranverein (Uranium Club); Powers remarks that even the word "club" is too formal for what was "an unruly mailing list of competing scientists". The situation is illustrated by the fact that Germany's only particle accelerator was held by the Post Office.

The German bomb never existed: even the German nuclear reactor, the peaceful project onto which Heisenberg claimed to have redirected government attention, was barely in existence at the end of the war. The only "secret history" behind this state of affairs is the entire complex and scattered story of atomic research under the Nazis. Powers does not tell that story: physicists other than Heisenberg appear from time to time, but what they all did during the war is unclear. Nor does he follow the course of the war and its effects on atomic research; nor does he consider the political differences between Heisenberg and other physicists in the US, in occupied Europe and in Germany. Instead he tells the tale of Heisenberg: how Heisenberg stopped the Nazi bomb programme in its tracks, how Heisenberg proposed a pre-emptive nuclear freeze, how the Allies responded by trying to kidnap or kill him.

There is something deeply unsatisfactory here. It is hard to see that Heisenberg did anything of any significance either to resist the Nazis or to forestall the German atom bomb. Heisenberg and other German physicists worked on nuclear fission through the war; even if a German atom bomb was not a real possibility, their work brought it measurably nearer. Moreover, there is nothing to suggest that any of them - even Otto Hahn, who said he would kill himself if his work led to a bomb - would actually have refused to work on a German Manhattan Project: if, for example, nuclear fission had been discovered in 1929 rather than 1939, and Peenemünde had been devoted to the A-bomb instead of the V-2. The decision whether or not to build an atom bomb was a political choice, on which the humanitarian intentions of any individual scientist could have no effect - the Manhattan Project itself is witness to that.

Powers' attempt to rescue Heisenberg's war from ignominy also rests on the assumption that things could - should - have been different. He hints that the Allies should not have concluded that "there was nothing and no one on the other side they could trust" but should, presumably, have put their trust in people like Heisenberg. It is difficult to see what this might mean. As indicated above, Heisenberg had a lot of common ground with the Nazis: he might well have approved of a regime ruled by Speer, for example, a rational, technocratic fascism without the anti-Semitism and the ideological excesses of Hitler's Nazism. The question is whether such a regime might also seem worthy of the western Allies' trust - might at least seem a defensible choice of "lesser evil" as compared with Stalinism. In the triumphal afterglow of the end of Communism, a charmless revisionism has put this once unthinkable question on the historian's agenda. The answer, I hope, is still no.

Phil Edwards, 1993

A shorter version of this review appeared in New Statesman and Society