Hitler had set himself, or been set, specific guidelines for the introduction and use of new weapons. In 1940 he had given Ohnesorge the impression that he was not interested in having an atom bomb. Two years later, within a few weeks of taking office, Armaments Minister Speer accepted that Hitler “did not want the bomb for doctrinal reasons”.
During a conversation with Field Marshall Keitel, Foreign Minister Ribbentrop and the Rumanian Head of State Marshal Antonescu on 5 August 1944 only a fortnight after the 20 July attempt on his life, Hitler spoke of the latest German work on new explosives “whose development to the experimental stage has been completed”. He added that, to his own way of thinking, “the leap from the explosives in common use to these new types of explosive material is greater than that from gunpowder to the explosives in use at the outbreak of war”. When Marshal Antonescu replied that he hoped personally not to be alive when this new substance came into use, which might perhaps bring about the end of the world, Hitler recalled reading a German writer who had predicted just that: ultimately it would lead to a point where matter as such would disintegrate, bringing about the final catastrophe. Hitler expressed the hope that the scientists and weapons designers working on this new explosive would not attempt to use it until they were quite sure that they understood what they were dealing with.
There can be little doubt that the subject under discussion was fissionable weapons material and, if that is so, then Hitler confirmed that the Germans had the weapon and that it was ready for testing in August 1944. The actual test took place two months later.
The difficulty with all these new weapons was the same, Hitler said. In general, he had ruled that a weapon should be brought into use immediately if it was guaranteed to bring the war to a victorious conclusion forthwith. This rule held good even if no counter-measure had yet been devised. In the majority of cases, however, the probability existed that the enemy would eventually obtain the same substance for himself, so the counter-measure was essential. Accordingly he had ordered that no weapon should be deployed by Germany first until Germany had developed the counter-measure to it.
SS-Obersturmbannführer Otto Skorzeny stated that when he saw Hitler in November 1944 their conversation came round to the atom bomb. Hitler said,
“Of course! But even if the radioactivity could be controlled, and you used fission as a weapon, then the effects would be terrible … it would be the Apocalypse. And how would one keep such a thing a secret? Impossible! No! No nation, no group of civilised people could take on such a responsibility. The first bomb would be answered by a second and then humanity would be forced down the road to extinction. Only tribes in the Amazon and the primeval forests of Sumatra would have a chance of survival.”
We must now place ourselves in the shoes of the 20 July plotters determined at some stage to overthrow Hitler. The U-boat offensive in the Atlantic had been defeated. German cities and industry were being pounded day and night by bomber fleets which roamed across Reich airspace with impunity. The Army and Waffen-SS were close to exhaustion, defending the ever-shrinking perimeter of Greater Germany. The situation was not completely hopeless, but it would not be long before it was.
Ernst von Weizsäcker, the father of Heisenberg’s close colleague, was Under-Secretary of State at the German Foreign Office, where he was one of the opponents of the Nazi regime. In 1938 he had informed the British Foreign Office of the existence of a group of civilian and military leaders ready to overthrow the Nazi Government if Hitler should go to war over Czechoslovakia, and was himself a major conspirator in what appears to have been the best-prepared coup ever planned against Hitler.
But Chamberlain and Lord Halifax, who had been asked to provide a strong demonstration of their determination not to tolerate the assimilation of the Czech state, disregarded the request, believing that an accord with Hitler was still possible. The German plotters were dismissed as Jacobites. The elder von Weizsäcker remained a focus of resistance in the Nazi State at war but was ultimately convicted at Nuremberg for alleged war crimes on the basis of his signature to certain documents.
According to Hitler’s Luftwaffe ADC Nicolaus von Below, the SS interrogations of the July 1944 plotters reported widescale treason by military leaders throughout the preceding four years: the preparations for the French campaign, the dates of the attack and the objectives of the first operations: even the beginning of the Russian campaign had been betrayed.
Long before the attempt on Hitler’s life the plotters had approached the Allied camp to establish terms for peace. Unconditional surrender was obviously not acceptable, yet, beyond that, all they got was encouragement to carry through their plans to overthrow Hitler. The Soviet author and former ambassador to Bonn, Valentin Falin, demonstrated by reference to Russian secret archives that the resistance movement penetrated to the highest military level in Germany and had contributed substantially to the success of the Allied invasion of occupied France in June 1944.
Professor Heisenberg, who in June 1944 had turned down an invitation by a Professor of History of his acquaintance, Adolf Reichwein, to participate in a plot against Hitler, frequented a social group known as the Mittwochgesellschaft(Wednesday Club). This was an intellectual forum of conservative opposition to Hitler composed of academics, civil servants and industrialists. Its members included the diplomat Ulrich von Hassell: General Ludwig Beck, the nominal head of the military conspiracy against Hitler; the philosopher Spranger; the Prussian Finance Minister Popitz; Ferdinand Sauerbruch, the Chief Surgeon of the German Army, and Rudolf Diels, the founder of the Gestapo. Reunions were held at the Harnack House in Berlin-Dahlem, the headquarters of the Kaiser Wilhelm Institute.
At the meeting of 12 July 1944 Heisenberg addressed the forum with a talk entitled “What are the Stars?” which appears to have been a cover for a discussion about nuclear fission. Spranger observed that these scientific developments promised to change the way men thought about the world, General Beck was more explicit and said that if atomic energy could be used for bombs then “all the old military ideas would have to be changed”. This implies that the question of the atom bomb must have been discussed. Just before leaving Berlin for his home at Urfeld on 19 July, Heisenberg delivered minutes of the meeting to Popitz. The attempt on Hitler’s life was made the next day.
Dr Kurt Diebner and ten assistants had set up an atomic laboratory in the cellar of a school at Stadtilm in the Harz, about thirteen kilometres from Ohrdruf, where Oberst Graf von Stauffenberg, the ringleader of the conspiracy, stayed regularly on the Wachsenberg, which was a favourite meeting place for officers and scientists working in the Ohrdruf area. Frau Cläre Werner, a watchtower lookout who resided on the mountain, recalled Stauffenberg visiting on a number of occasions and she still had possession of items of property he had left with her on his final visit. Why should Stauffenberg have come so often to Ohrdruf when he worked in Berlin? Did the German resistance movement have more than a passing interest in what was going on at Stadtilm and its subterranean environs?
The German author Harald Fäth reported that in the 1960s Gerhard Rundnagel, a master plumber who worked in the Stadtilm atomic research laboratory, gave evidence to a DDR judicial enquiry about the wartime activities there. In the depositions Rundnagel made a statement that the Stadtilm Research Institute had not been properly plumbed in and so was not really up and running. As far as he could see the scientists there were not actually working on anything. This left a lot of time for talk and Rundnagel described conversations he had had at the beginning of July 1944 with Dr Rehbein, a scientist at Stadtilm. Rehbein is alleged to have told Rundnagel that what was under development there was a type of bomb which had a greater explosive power than anything that an old weapons engineer such as himself could possibly envisage. Rehbein then went on to say, “Within a few days you will hear a decisive announcement on which will depend the outcome of the war.” On 20 July 1944 the unsuccessful attempt was made on Hitler’s life. When Rundnagel asked Dr Rehbein later if that was what he had meant, the scientist laughed and replied, “Now it will never be used. The war is lost.” There are two ways of looking at this statement. Rehbein may have been suggesting that once Germany could make the official announcement that an atom bomb had been successfully tested, Hitler would be in a strong position to negotiate with at least one of his enemies. Because of the conspiracy against him, however, the evidence of disunity and betrayal perceived by foreign governments abroad would reduce figuratively the bomb’s impact.
But there is an alternative interpretation. Along with other scientists in Dr Diebner’s entourage, Dr Rehbein may have been an associate of the anti-Hitler faction who wanted the Führer out of the way so that the German military could use the bombs physically to negotiate peace on terms more favourable than unconditional surrender. If it had become known to the resistance that, once tested, Hitler was resolved not to deploy the small atom bombs operationally, this would explain not only why the plotters struck when they did, but would justify Rehbein’s remark that the war was lost, for with Hitler remaining as leader the atom bombs would never be used, or at least would be used only in response to the enemy’s first use; yet the atom bomb, used in quantities, was, in the view of the plotters, Germany’s last hope. 95 The sense of the words attributed to Dr Rehbein seem to favour the latter interpretation.
The fantastic idea current in 1944 of the effect of even a small atomic explosion is conveyed by an article in the Swedish newspaper Stockholms Tidningen in August 1944, and reported in Germany by the TranSozean Innendienst news agency:
“In the United States scientific experiments are being carried out with a new bomb. Its explosive substance is uranium, and when the elements within its structure are liberated, a force of hitherto undreamed-of violence is generated. A 5-kilo bomb could create a crater one kilometre deep and of forty kilometres radius.”
In all the foregoing we have a possible explanation for Professor Heisenberg’s activities. Throughout the Hitler period he was opposed to the regime. He had remained in Germany in 1939 in order to sabotage the atom bomb and radiological warfare projects. In September 1941 he had taken a philosophical standpoint that a regime is to be considered evil by reference to the means it uses to impose its policies, and the atomic bomb was evil. In 1943 the United States had begun work on its atomic arsenal, a fact of which he would probably have been aware. In Germany a strong military resistance was developing of which Heisenberg had knowledge. He knew from von Weizsäcker that terms for an honourable conclusion to hostilities other than unconditional surrender were not available to Germany if that resistance succeeded in overthrowing Hitler. Heisenberg was a patriot. War was war, and, with Hitler removed, what German wanted Stalin or Roosevelt running the country? Therefore the idea of building a bomb of some description had been forced on him, for there had to be some sort of bomb, a bomb inevitably designed and built during the chancellorship of Hitler as Führer, but intended for use in diplomacy by those who would succeed him.
This pre-supposed, of course, that Hitler actually could be got rid of. The suggestion has been made in various quarters that he was in some way under the protection of higher powers determined that he should see his mission through. No assassination attempt could ever succeed because there would always be the hand to re-position the offending attaché case with its bomb, or Hitler would change his schedule unexpectedly and leave the building minutes before a bomb went off. As was referred to in the Introduction, two well-placed authorities who observed Hitler pre-war had the impression that he was a medium, and mediums do claim that nothing can harm them seriously during the times when they are possessed by gods or spirits.
If the plotters had succeeded on 20 July 1944, and the SS had not taken over the running of the country in the aftermath, the death camps would presumably have been abolished, but one sees no easy way how a continuation of the war against the Western Powers could have been avoided. Probably Germany would have found Stalin willing to re-align the Soviet Union in some manner with the new Reich and possibly Japan, particularly if a demonstration of the new explosives or the nerve gases could have been arranged. Whether that was something which the supporters of the plot against Hitler would have found acceptable as the price of removing him we have no means of knowing.