Conspiracy​ theories cluster around violent and unexpected political events. The sudden death of a head of state, the assassination of a government minister, a bomb attack on a building or a crowd: these seemingly random occurrences demand explanation, and for many, the idea that they could be the product of the deranged mind of a single individual seems too simple to be plausible. The authorship must surely have been collective, the planning long-term and meticulous. The killing of John F. Kennedy in Dallas in 1963, or the destruction of the Twin Towers in New York in 2001, are the two major vortices into which conspiracy theorists have been sucked in our own time, generating ever more elaborate explanations and pseudo-explanations. Argument continues to rage, as the proponents of rival theories construct evidential edifices of such staggering detail and complexity that they are often almost impossible for a lay reader to navigate.

Alternative histories of this kind have a long history. Just over eighty years ago another major and wholly unpredicted violent event occurred in Berlin, then early in the transition from the Weimar Republic to the Third Reich, with Hitler installed as chancellor but not yet in possession of dictatorial power. Just after nine o’clock on the evening of 27 February 1933, passers-by heard the sound of breaking glass coming from the Reichstag and, shortly afterwards, saw flames beginning to light up the inside of the building. Fire engines were summoned and brought the blaze under control, but it was too late to save the debating chamber. Arriving on the scene, Hitler, Göring, Goebbels and the interior minister, Wilhelm Frick, declared that the arson attack was a Communist plot, designed, as Goebbels put it in his diary, ‘through fire and terror to sow confusion in order in the general panic to grasp power for themselves’. ‘You are now witnessing the beginning of a great new epoch in German history, Herr Delmer,’ Hitler told the Daily Express reporter Sefton Delmer, who also arrived at the scene. Göring ordered the mass arrest of Communists, and Nazi stormtroopers, already enrolled as auxiliary policemen, fanned out across the capital, picking up party activists and taking them to makeshift prisons and torture centres.

The next morning, the cabinet, which still had a non-Nazi majority, met to draw up an emergency decree that abrogated civil liberties across Germany. Signed by President Hindenburg the same day, it abolished freedom of speech, freedom of assembly and association, and freedom of the press, suspended the autonomy of federated states, such as Baden and Bavaria, and legalised phone-tapping, the interception of correspondence and other intrusions. This was the first of the two fundamental documents on which the dictatorship of the Third Reich was erected. The Enabling Act, passed, thanks to Nazi intimidation, by the Reichstag on 23 March, assigned exclusive legislative power to Hitler and his ministers, bypassing the president and the Reichstag. This was the second. The crucial emergency powers granted to the government by the decree of 28 February were periodically renewed right up to 1945. The Nazis used them to bludgeon their opponents into submission and their allies into compliance. By the summer of 1933 all opposition had been crushed, more than a hundred thousand Communists, Social Democrats and other opponents of the Nazis had been sent to concentration camps, all independent political parties had been forced to dissolve themselves and the Nazi dictatorship had been firmly established.

The Third Reich was founded on a conspiracy theory. The Communists, the Nazis’ most implacable opponents, had won 17 per cent of the vote in the last completely free elections of the Weimar Republic, in November 1932, increasing their support while the Nazis dropped back. They had never made any secret of wanting to destroy Weimar democracy and create a Communist state. It seemed obvious to Hitler that the destruction of the Reichstag could only be the result of a Communist plot to seize power. The Nazi leadership proceeded therefore to charge a number of Communists with conspiracy. A wave of propaganda convinced many middle-class Germans that the emergency decree was justified.

During the blaze, the police found a young Dutchman called Marinus van der Lubbe in the building. He had firelighters in his possession and other suspicious material. By the time he was brought to trial before the Supreme Court in Leipzig, he had been joined in the dock by Georgi Dimitrov, head of the Central Europe Section of the Communist International, two other Bulgarian Communists who had been in Berlin at the time of the fire, and Ernst Torgler, chairman of the German Communist Party in the Reichstag. The trial was a fiasco. Dimitrov ran rings round the prosecution, reduced Göring, who appeared as a witness, to incoherent rage, and mocked the Nazis’ conspiracy theory with wit and panache. The trial judges, led by Wilhelm Bünger, a conservative but not a Nazi, a former minister-president of Saxony, found that the Communists had planned the fire, but dismissed the charges against Torgler and the three Bulgarians on the grounds of insufficient evidence.

Van der Lubbe was found guilty, sentenced to death and executed in accordance with a Nazi decree postdating the fire that made arson subject to capital punishment – the first of many Nazi violations of fundamental legal principles. The Nazis did their best to make political capital out of the verdict, but privately Hitler was furious. He quickly set up a new system of special courts, crowned by the so-called People’s Court, to bypass the clearly unreliable traditional legal system and deliver the verdicts he wanted in future cases. But Torgler and the Bulgarians could not be tried again (double jeopardy was a principle even the Nazis were unwilling to violate at this point), and they were eventually released; after secret negotiations they made their way to the Soviet Union. Dimitrov would become the first Communist leader of Bulgaria after the war. Torgler, probably to save his son from the violent retribution threatened by the Nazis, began working for the Gestapo and eventually took a minor post in the Propaganda Ministry, a move that caused him considerable problems after the war.

Before the trial had even begun, Dimitrov and the Communist propaganda apparatus, under the enterprising leadership of the legendary Willi Münzenberg, had developed their own conspiracy theory about the fire. The Nazis had benefited, so the Nazis must have started it. Münzenberg and his team rapidly put together The Brown Book on the Reichstag Fire and Hitler Terror, published in London in the same year. Aside from the numerous, undoubtedly genuine and often moving accounts of Nazi brutality by its victims, The Brown Book presented ninety pages of documentation purporting to show that a Nazi team of arsonists, led by a prominent brownshirt called Edmund Heines, had entered the Reichstag through a secret tunnel from Göring’s official residence, set light to the building in many places, then gone back through the tunnel to safety, leaving the hapless van der Lubbe to take the blame. The book put particular weight on a memorandum blaming the Nazis supposedly written by Ernst Oberfohren, the parliamentary leader of the Nationalist Party, allies of the Nazis.

The Brown Book, backed up by a sensational mock trial in absentia of the supposed Nazi authors of the blaze, held before carefully selected international judges in London, put the Nazis on the defensive. Münzenberg had achieved a propaganda coup. The allegations of The Brown Book were widely believed: here, it seemed, was a conspiracy theory that could be trusted. Yet after the war, despite a massive programme of denazification and prosecution, no new arsonists were identified. The amnesiac political culture of West Germany at the time worked against any attempt to identify Nazis who might have been involved. In East Germany, The Brown Book continued to be regarded as gospel truth, and no point was seen in pursuing the matter.

Then, in 1959, a series of articles appeared in Der Spiegel, arguing that van der Lubbe had acted alone. Three years later, the research they were based on was published in greatly expanded form in a book by the previously unknown Fritz Tobias, entitled The Reichstag Fire: Legend and Reality. In well over seven hundred pages it presented meticulously detailed analyses of the evidence backed by an enormous quantity of careful research in support of the thesis that van der Lubbe had been the only person involved.

Among other things, Tobias produced contemporary evidence which demonstrated that Oberfohren had not written the memorandum. He pointed out that van der Lubbe had always denied anyone else was involved in the arson, and had greeted Dimitrov’s claim to the contrary in court with open amusement. The expert witnesses called to explain how the fire had spread so quickly testified that the fires must have been laid with incendiary liquids at a number of points simultaneously – but they knew that failure to conclude that van der Lubbe was part of a Communist conspiracy would have brought them into serious danger.

Tobias noted that no traces of flammable liquids or containers had been found at the site of the fire. He also exposed massive contradictions in the accounts given by a number of those close to the action and showed that after the war they had amended their accounts in order to present themselves in a good light. The book was a formidable challenge to the Communist version of events.

The vehement and dismissive language Tobias used marked his book as the work of an outsider to the historical profession, but it received crucial backing when the Institute for Contemporary History in Munich, Germany’s leading centre for research into National Socialism, commissioned the young historian Hans Mommsen – who would in time become the doyen of Third Reich historiography – to investigate the matter. Mommsen backed Tobias in a powerful article and went on to argue that the Nazis were opportunists who had seized on chance occurrences to further their own purposes. This became known as the ‘functionalist’ interpretation of power in the Third Reich, as opposed to the ‘intentionalist’ view that saw everything as the deliberate outcome of Hitler’s plans.

The proponents of the conspiracy theory that held the Nazis responsible were not going to let the matter rest here. Münzenberg was long since dead, murdered in 1940 in the French Alps on his way to the Swiss border, probably by an agent of Stalin’s secret police. He had become inconvenient, caught in the pincers of the Nazi-Soviet Pact. But by the 1960s a new generation was ready to revive his conspiracy theory. The most active was a Croatian journalist called Edouard Calic, born in 1910. While studying in Berlin during the war, Calic had been suspected of taking part in ‘plot-like conspiracies’ and spying for the British. He was imprisoned at Sachsenhausen but survived, and after the war stayed in Germany.

Calic said he was outraged by the findings of Tobias, whom he defamed as a ‘Nazi of the first hour’, though he was in fact a lifelong Social Democrat. He began publishing evidence that he claimed proved that the Nazis had started the fire after all, but critics soon began to spot anomalies. In 1968 he published, as a book, transcripts of two interviews with Hitler allegedly conducted in 1931 by a senior newspaper editor called Richard Breiting, and subsequently supposedly buried by him in a canister in his garden because he feared for his life should they be discovered. The interviews showed Hitler was making plans to burn the Reichstag two years before the event. ‘In my opinion,’ he is recorded as saying to Breiting, ‘the sooner this talking shop is burned down, the sooner the German people will be freed from foreign influence.’ The anomalies piled up, however, and Hugh Trevor-Roper and others immediately denounced the book as a forgery. Suggestively entitled Unmasked, it had obviously been in large part, if not completely, made up by Calic himself. I used to give the book to my students and ask them to decide whether it was genuine; they had no difficulty in concluding that it wasn’t.

Despite the doubts expressed by Trevor-Roper et al, though, many serious historians praised Unmasked. Building on this success, Calic formed a committee to research the origins and consequences of the Second World War – the so-called Luxembourg Committee. In 1972 and 1978 the committee produced two large volumes of documents and commentary (Der Reichstagsbrand: Eine wissenschaftliche Dokumentation), containing old and new expert witness reports, the testimony of a number of firemen who fought the blaze, excerpts from the testimony of van der Lubbe, and more than fifty pages analysing the evidence concerning the underground passage. Tobias and Mommsen were accused of deliberately falsifying the reports of the expert witnesses. A particular feature of the volumes, however, was their claim that a whole series of inconvenient witnesses of the Nazis’ responsibility for the attack died soon after the fire, above all in the Night of the Long Knives, Hitler’s purge of the stormtrooper organisation at the end of June 1934. Oberfohren was found dead at his desk just a few weeks after the fire, and Breiting died, supposedly poisoned by the Gestapo, in 1937. Mysterious deaths are a key part of many conspiracy theories.

The two imposing volumes were also accused of containing forgeries and falsifications, first in a series of articles in the liberal weekly Die Zeit in 1979 and then in Reichstagsbrand: Aufklärung einer historischen Legende, a volume published in 1986 with contributions by Mommsen, Tobias and others. Most of the committee’s documents were not made available to historians to check, or appeared only as excerpts; almost all of their authors were dead so could not be questioned about them; and they contained numerous contradictions of known facts.

One of the forged documents drew its inspiration from the report of a talk with Göring recorded in Hermann Rauschning’s Conversations with Hitler, published in 1940. Rauschning, a renegade Nazi, wrote that Göring had admitted responsibility for the fire, but when his attention was drawn to this passage at Nuremberg, Göring said he had only met Rauschning twice in passing, and would never have made such an admission to a stranger. In fact, nothing was genuine in Rauschning’s book: his ‘conversations with Hitler’ had no more taken place than his conversations with Göring. He had been put up to writing the book by Winston Churchill’s literary agent, Emery Reeves, who was also responsible for another highly dubious set of memoirs, the industrialist Fritz Thyssen’s I Paid Hitler.

Calic himself was revealed to have lied about his own past: he claimed to have been imprisoned in Sachsenhausen in 1941 but wasn’t sent to the camp until February 1943. His assertion that he had obtained documentary evidence of the Nazi responsibility for the Reichstag fire from one of the 1944 military conspirators against Hitler whom he had met in Sachsenhausen was revealed to be an invention since there was no record of the conspirator actually having been there. A court case in 1982 ruled that it was legitimate to describe Calic as a ‘shady character’. Finally, on 9 March this year Die Welt revealed that in 1961 Calic had informed the Stasi about a route used by East Germans to escape to the West. A true disciple of Münzenberg, he evidently believed that forgery was justified by the political effect it produced.

In the end Calic only succeeded in convincing the bulk of the historical profession that Tobias was right, and that the sole author of the Reichstag fire was Marinus van der Lubbe. Significantly, East German historians did not intervene in the dispute, passing over Tobias’s work and its critics, preferring instead to join with Bulgarian and Soviet historians in publishing previously unavailable (and undoubtedly genuine) documents from their archives in 1982 and 1989 as Der Reichstagsbrandprozess und Georgi Dimitroff.

In​ the 1990s, however, dissenting voices could be heard once more. In 1992, a political scientist, Alexander Bahar, a student of the titular head of the Luxembourg Committee, reissued the committee’s documentation as, he said, an act of ‘resistance against fascist tendencies’ in the newly unified Germany. Eight years later, together with Wilfried Kugel, he published a book of more than eight hundred pages, presenting the same arguments again but using evidence from the police investigation records, trial documents and interrogation protocols discovered in the East German archives after the fall of the Berlin Wall. This new attempt to vindicate The Brown Book and its successors was roundly dismissed in a series of hostile reviews. Even the more neutral reviewers concluded that the new documentation, while useful, proved nothing.

Kugel, described as a physicist and psychologist, was registered with the Parapsychological Association of America, so it was hardly surprising that among the evidence the book presented was a report of a séance held in Berlin the night before the fire, in which the police chief, von Helldorf, asked a medium: ‘Will our great plan to secure power succeed?’ The hint that this referred to the Reichstag fire had, of course, no basis in reality. Even more bizarrely, Bahar and Kugel suggested that the clairvoyant might have hypnotised van der Lubbe into allowing himself to be used by the Nazis.

In a lengthy article in Der Spiegel and a short book, Der Reichstagsbrand: Die Karriere eines Kriminalfalls, published in 2008, Sven Kellerhoff, an editor at the conservative daily paper Die Welt, systematically took Bahar and Kugel’s work apart, and with it the whole conspiracy theory that went back to The Brown Book. He pointed out once more that no traces of flammable liquids had been found after the blaze. There was no evidence that the underground passage to Göring’s residence had been used: Tobias had already pointed out that the underground tunnel was more or less impassable because filled with steam pipes from a boiler room located for safety reasons away from the main building; it was in any case almost impossible to get into the Reichstag through the maze of corridors and locked doors at the end of the tunnel. Kellerhoff noted that of the stormtroopers who had supposedly set the fire, Hans Georg Gewehr had demonstrably no connection with the deed, while another, Adolf Rall, had been in a remand prison at the time. If the Nazis had come through the passage, set the building alight, then gone back the way they had come, he asked, why did passers-by hear the sound of broken glass just before the fire began?

Kellerhoff’s​ book might have been thought to have set the matter to rest. But now a fresh attempt has been made to vindicate the theses of The Brown Book. It comes from an American lawyer and historian, Benjamin Carter Hett, who made his name with a well-researched and passionately written biography of the left-wing lawyer Hans Litten, whose humiliation of Hitler in a cross-examination during the trial of a group of stormtroopers towards the end of the Weimar Republic led to his arrest on the night of the Reichstag fire and treatment of such brutality in the camps that he eventually committed suicide. The book deservedly won the Fraenkel Prize for Contemporary History (I was on the jury that awarded it). Hett’s interest in the Reichstag fire was evidently kindled by this earlier work.

His new book, Burning the Reichstag, rests on material found in two dozen archives in several countries, some, like the Stasi archives, not consulted by previous researchers, as well as on private collections (notably that of Tobias), correspondence and interviews. It is an impressive piece of work that presents fresh evidence and puts its theses forward with far greater sophistication than earlier defenders of The Brown Book’s arguments. It is well written and highly readable. But it is the work of a prosecuting attorney rather than of a balanced historian.

Hett’s book fails to engage directly with much of the previous literature: Kellerhoff’s book is mentioned only twice, for example, and its arguments are not confronted. Historians who have accepted Tobias’s conclusions are dismissed as ignorant or careless on the basis of a handful of extremely minor errors, a tactic which diverts attention from the substantive issues. Hett’s preferred method is the classic courtroom tactic of discrediting witnesses. Thus the Gestapo chief Rudolf Diels, who did not believe there was a Nazi conspiracy, is discredited because the Gestapo was pro-Nazi and corrupt, and anyway he was a womaniser and thus immoral and unreliable, while a rival Gestapo official, Hans Bernd Gisevius, whose testimony in favour of the conspiracy thesis Hett likes, is described as ‘an early opponent of Hitler’s rule’ although in 1933 he was busy locking up Communists and other genuine opponents of the Nazis. The judicial and police apparatus at the time of the fire was in any case not yet Nazified, as the thousands of prosecutions brought against violent stormtroopers, and later quashed on Hitler’s orders, indicate.

He portrays Tobias as a Nazi who admired Hitler and who as an official in the Netherlands during the war carried out activities that ‘could have involved exposing Jews to deportation’, an allegation typical of the innuendo that is his stock-in-trade. After the war, Hett claims, Tobias was friendly with old Nazis; he also complains that a new edition of Tobias’s book was published in 2011 by the far-right press Grabert Verlag (at the time of the agreement to publish, Tobias was terminally ill, and the book only came out after his death). He doesn’t mention that Tobias’s critics’ work appeared mostly from obscure left-wing publishing houses.

Tobias was friendly with many people, including left-wingers like van der Lubbe’s former comrades in the Netherlands. Hett, following earlier allegations by Calic, claims Tobias allowed himself to be used as the mouthpiece of former Gestapo officials who feared prosecution in the 1950s for their part in the fire, though such men would have known that the likelihood of prosecution was extremely slim, given West Germany’s dismal record in prosecuting war criminals and the fact that the statute of limitations gave immunity from prosecution for a crime such as arson committed in 1933.

Hett claims that Tobias worked for the intelligence service and used the information at his disposal to blackmail the Institute for Contemporary History into vindicating his own views by threatening to expose the Nazi past of the Institute’s director, Helmut Krausnick (this was no secret, and Krausnick’s many contributions to the prosecution of Nazi war criminals over the years made the fact more or less irrelevant).

In building up his case, Hett deploys a whole armoury of suggestion and innuendo. He provides detailed evidence that stormtroopers were trained in the use of fire-raising equipment with kerosene and rags, which they used to set light to advertising columns displaying anti-Nazi posters, but this in no way proves that such training was intended to prepare for the burning down of the Reichstag. He goes into detail about the stormtroopers’ murder of inconvenient witnesses, but is completely unable to demonstrate that they were murdered because they were (supposedly) witnesses to the fire. He does admit Oberfohren most likely committed suicide, but tries to rescue the views he allegedly expressed in the (forged) memorandum, though these were no more than hearsay.

As for the stormtroopers’ supposed recruitment of van der Lubbe as a stooge, all Hett can say is that he seems to have met a Communist activist called Walter Jahnecke some days before the fire, that Jahnecke might have been a police agent, and that his friend Willi Hintze, who also met van der Lubbe at a flat where he was staying for the night on 22 February, was definitely a police agent. This apparently makes Jahnecke and Hintze ‘plausible candidates for having brought van der Lubbe into the orbit of the SA’. Other than this tissue of supposition, however (the two men were not members of the SA), there is no evidence at all that the arsonist had any contact with stormtroopers before the fire. Surely it would have taken a lot more than an evening spent in a flat with two men who claimed to be Communists and were generally believed to be so to secure him as a stooge in an operation as elaborate and dangerous as burning down the Reichstag. And while the supposed leader of the arsonists, Hans Georg Gewehr, in later years dropped dark hints that he had taken part in the action, he was a notorious drunkard whose command over truth and memory was extremely shaky. When Gisevius named Gewehr as a main suspect, he believed him to be dead, but he was very much alive, and emerged successfully from the historical woodwork to sue Gisevius for libel, and win.

Hett points out that the decree suspending civil liberties had been prepared long before the fire, but this does not show that the Nazis planned to burn down the Reichstag, merely that they intended to suspend civil liberties, and that senior civil servants had drawn up contingency plans for this well before the Nazis came to power. Lists of Communist Party members were also drawn up by the police long before the fire, but again, this does not show that the fire was pre-planned, simply that the police expected at some point to arrest these people.

Hett passes over evidence that goes against his argument. Hitler’s intimate Ernst ‘Putzi’ Hanfstaengl, barfly and man about town, who broke decisively with the Nazis in the mid-1930s, later remembered being woken up by the shouts of the housekeeper as he dozed in bed in a room in Göring’s official residence, which had a clear view of the Reichstag. He looked out of the window and saw the building on fire. He phoned Goebbels to tell him the news. Goebbels thought the notoriously frivolous Hanfstaengl was joking and refused to tell Hitler. But after making some inquiries he concluded the report was true, and it was at this point that he and Hitler made their way to the scene. Why would Hanfstaengl lie about this, when he was willing to spread all kinds of scurrilous gossip about the leading Nazis? His story was also corroborated by the memoirs of Sefton Delmer. But Hett does not mention that.

Kellerhoff argued that the policemen who had investigated the fire, Helmut Heisig and Walter Zirpins, were right to conclude that ‘the question of whether van der Lubbe carried out the deed alone may be answered in the affirmative without further consideration.’ He had climbed in through a window after breaking the glass: fingerprints, unidentifiable because of the rough surface, were found on the window-ledge. Once inside, he ran through the building, finding the right target finally in the curtains of the main chamber, which he set alight, causing a fire that spread rapidly, leading to an explosive combustion or backdraft (Hett’s attempt to discredit this point in an endnote is unconvincing). If the Nazis had really lit the fire that killed the Weimar Republic, why did they not plant evidence of Communist conspiracy in the Reichstag? This was their standard practice, used for example in their attempt to attribute to the Polish government an attack on a German radio station at Gleiwitz in 1939 that they carried out themselves as a pretext for launching hostilities. On that occasion they left bodies lying around (concentration camp inmates dressed in Polish uniforms) and it seems obvious that they would have done something similar if they had planned the Reichstag fire.

Why did Delmer find the Nazi leaders in a state of panic when he arrived on the scene? If Goebbels had been involved in the preparations why didn’t he mention them in his private diaries, when he describes preparations for far greater crimes, including the mass murder of Europe’s Jews? Hett claims that Goebbels must have omitted them because he knew the diaries would be published, but in 1933 he was publishing only carefully edited extracts: the intention to publish everything, signalled by his switch from writing to dictating, came only later. Even in 1938, when he publicly described the pogrom of 9-10 November as a spontaneous outburst of popular anger against the Jews, Goebbels recorded in his diary that he himself had orchestrated it.

Crucially, Hett is unable to deal convincingly with the problem of van der Lubbe. Why would the Nazis have chosen him as their stooge when he was not even a paid-up member of the German Communist Party or any other Communist organisation? There is no more evidence to back up Hett’s claim that he was drugged by the Nazis during his trial to stop him revealing the fact that he had acted on their behalf as part of a larger group of arsonists than there is for Bahar and Kugel’s suggestion that he was hypnotised. Van der Lubbe, Hett tells us, had poor eyesight as a result of an industrial accident, but he was not so blind as to fail to recognise large pieces of furniture, doors and other obstacles in his passage through the building. Contemporary reports describe him as panting and sweating profusely when he was arrested, as he would have been had he just rushed through the building rather than hanging around as a Nazi stooge or acting in concert with others. In endless hours of interrogation, van der Lubbe never deviated from his story that he had acted alone, and never once accused the Nazis themselves of being behind the crime. His confession remains a compelling piece of evidence.

Rejecting​ the thesis of Nazi guilt does not commit one to seeing the fire, as Tobias did, as a random event. The Nazis would have found an excuse to curtail civil liberties and eventually abolish them without the fire. Everything suggests that the momentum towards the establishment of a dictatorship was fast becoming irresistible. Van der Lubbe’s act was not really random: a former anarcho-syndicalist, he had already tried unsuccessfully to set fire to a series of public buildings in protest against the political and social system he held responsible for mass unemployment – nearly 40 per cent, an almost unimaginable figure even in today’s recession. Without the Depression, there would have been no compelling reason to set the symbols of bourgeois rule alight.

According to Hett, Tobias’s conclusion, that the Reichstag fire was a ‘blind chance, an error’ that ‘unleashed a revolution’, amounts to ‘effectively erasing from the historical record the Nazis’ lust for power and the ruthlessness with which they sought it’. Tobias’s work therefore reeks of ‘apologetic intentions’, not least because it pins the blame for the blaze on a non-German. Hett presents no direct evidence for this misrepresentation of Tobias’s purposes; there is plenty in Tobias’s work to refute Hett’s claim that he believed there was ‘no long-term strategy … behind Hitler’s entire bid for power’ – for example, his contextual section on ‘Germany 1932’. For Mommsen and Kellerhoff, on the other hand, the persistent attempts to vindicate The Brown Book and portray the fire as a carefully planned operation threatened to exculpate the role of the German people in the creation of the Third Reich by portraying them as victims of a deliberate conspiracy to seize power instead of accepting their complicity in the process.

There is no evidence that Tobias intended to provide excuses for the Nazis or underplay their violence or lust for power: on the contrary, he pointed out, in a passage not cited by Hett, that the Nazis committed far greater crimes later in their rule so that ‘their guilt is too great for this supposed “exculpation” to carry any weight.’ Far from being only ‘nominally a Social Democrat’, Tobias was a genuine and long-term member of the party. His real concern, typical of a moderate Social Democrat, was the polarisation of right-wing and left-wing views during the Cold War, which was reaching its height when his book appeared in 1962, the year of the Cuban Missile Crisis. He saw it as replicating the polarisation of politics in Germany in 1932-33. In such a situation, he thought, a single event could lead to unimaginably disastrous consequences; and he ended his book with a quote from Bertrand Russell, whose uncompromising campaign against nuclear weapons he clearly applauded.

For Münzenberg and later Calic and the Luxembourg Committee, conspiracy theories came naturally in a Communist movement that had seen Stalin launch trials of plotters and saboteurs, just as he would soon stage the show trials that portrayed many leading Old Bolsheviks as part of a vast conspiracy to overthrow the Soviet Union. This tradition has long since come to an end, but it has been replaced with a new form of conspiracy theory in the internet age. Hett’s book is permeated by it: the Nazis conspired to burn down the Reichstag, Tobias conspired with ex-SS men to deny it, Krausnick and Mommsen conspired to deny the Nazis’ involvement. Conspiracy theories aren’t necessarily wrong, and in some cases there is compelling evidence that conspiracies did lie behind major historical events. But not this one.