There are some minor inaccuracies in terms of casting and acting which were likely done for dramatic license. For example, Ian McNeice's scenery-chewing Gerhard Klopfer is far more rotund than the actual Klopfer. Conspiracy's porcine Klopfer is an avatar for NSDAP corruption and the overbearing swagger of the party's apparatchiks. The film's portrayal of Heydrich is in line with older historiography of the man as a cipher in which brutality became a means to an end. In an interview with Tribune News Service Branagh explained his performance as Heydrich:

He was enjoying, it seemed, a craven exercise in absolute power. This is both chilling, it's also very gripping. But to play it is very, very disturbing and unusual -- unusual and unsettling for the actor. . . . It was very disturbing. I suppose you could end up saying he was a fantastically efficient executor of an absolutely extraordinary, awful and desperate plan. But it was very hard to find what was human inside him.

This view of Heydrich as the inhuman id of genocide does not really square with the current research both in Heydrich and of the RSHA conducted by the likes of Michael Wildt and Robert Gerwarth (which, to be fair to Branagh, the main works had largely yet to be published). Gerwarth's biography of Heydrich presents the man as who committed genocide but whose chilling public persona was in many respects the creation of a man who had been promoted far beyond what he could have expected; Heydrich, for example, had no police background beyond consuming detective novels, but now was the head of a statewide, and later continent-wide, security agency.

But the above problems are relatively niggling and minor. The real "problem" of Conspiracy is that it hews to one particular interpretation of the Conference. Argued quite forcefully by the likes of Christian Gerlach-pdf warning, this historiographical interpretation of the Conference contends that the coded language employed by the Conference was a euphemism for immediate murder. The film's title and the dialogue's repeated reminders of the importance of words and their meaning underscores an interpretation of the Conference in which it was a Rubicon in which mass genocide on a continent-wide scale was accepted. Screenwriter Loring Mandel's scriptnotes observes that the idea of gassing floated at the Conference represented "the crossing of some previously accepted moral boundary." References to the Einsatzgruppen mass shootings, disease in the Polish ghettos, and mentions of Auschwitz all point to gas chambers and industrial genocide as the logical terminus of German Jewish policy. Postwar testimony, especially Eichmann's trial, added further weight to this interpretation and such a view of the Conference does lend itself narrative force. The result is that the film has a true villain, the SS heads, who want to cut the Gordian knot and be done with the Jewish problem once and for all.

This is not the only interpretation of the Conference though. Pace Gerlach, historians like Saul Friedländer and Peter Longerich have contended that the Conference's vision of a Jew-free Europe was not as nearly as comprehensive nor as ambitious in scope. Longerich argues that genocide was more open-ended and that while industrial mass murder was considered, it was more limited to the Jews of the General Government. Himmler and the RSHA were still floating ideas after the Conference of using European Jews as a mass labor force where they would be worked to death. Subsequent ministerial meetings on the status of Mischlinge individuals further support this interpretation that the Conference was far less decisive for German policy than popular memory holds it. The importance of the Conference in the larger scheme of the Holocaust according to these historians was not that it was the place where systematic genocide was decided, but rather the SS both cemented its role for the formulation Jewish policy and received permission from the various state ministries for the deportation of Jews throughout Europe. Both of these achievements were decisive for Jewish policy to evolve into industrial genocide.

Neither of these two interpretations of Wannsee are the final word on the matter, nor can they be. The surviving minutes of the Conference are so tersely edited down that a literal reading of them does not reveal much about German policy beyond they were looking at the total number of European Jews and would evacuate them to the East. Denialists like David Irving have taken a literal interpretation of the minutes to argue that the Conference was much ado about nothing, and while this is pedantic and lazy nonsense, it does underscore the paucity of detail contained within the minutes themselves. Historians have to look at the broader context of events and evidence outside of the Conference to parse out its wider importance for the evolution of the Holocaust. In interviews for the film, Mandel called his narrative for Conspiracy "informed speculation," and in this respect, his efforts are not that dissimilar to how historians analyze a specific event. The simple fact is we do not know with total certainty what exactly was said in the Conference. The film's picture of Wilhelm Stuckart is useful to contrast with those of historians. Gerwarth's biography of Heydrich contends that:

Heydrich's proposals did not encounter much opposition from the other delegates. Stuckart's only concern was that the proposed measures involved "endless administrative work". He therefore suggested as an alternative the complete sterilization of the Mischlinge population, a suggestion supported by the director of the Race and Settlement Office, Otto Hofmann.

This is slightly different view of the State Secretary than Conspiracy's view of Stuckart, whose defense of the Nuremberg Laws was more acrimonious and represented the acme of the participants' friction against mass genocide. While Gerwarth's version of events (concern) is squared with Stuckart's later engagement with Himmler over the legal status of the Mischlinge, but it is not outside the realm of possibility that Stuckart did express such concerns forcefully during the Conference.

This sort of creative license inherent to dramatization illustrates one of the greater strengths of Conspiracy vis-a-vis the historical record. Loring Mandel's script uses the grey areas and blanks in the past to read between the lines of the Conference's minutes. While the participants of the Conference may not have registered dissent over the SS's ascendancy in the power hierarchy during the Conference, this was a notable source of friction between the SS and other state agencies and the film does dramatize this apprehension that was intrinsic to a polycratic structure like the Third Reich (and this is one area in which Conspiracy does a better job than the German film Die Wannseekonferenz which paints a much more genial picture of camaraderie between the participants). Conspiracy tacks to an interpretation of Wannsee that perhaps makes too much of a case that it was a crystallizing moment in the development of the Holocaust, but the film's "informed speculation" is not that far from historians' view of what occurred on 20 January 1942.