I'm convinced the Holocaust happened and I'm convinced Hitler had knowledge of it. Why? Because he was a raving anti-Semite, who stated that he wanted to purge Europe of Jews. And, bluntly, he was the Furher. Claiming Himmler and Heydrich could have conducted the Holocaust without Hitler knowing anything is absurd.
Which brings us to the non-existance of the Hitler Order. But does it have to exist? It is reasonable to assume Hitler had knowledge of the Holocaust and it could not have happened without his authorisation, regardless of whether a physical copy of the order is ever located - unless good evidence to the contrary can be produced. If deniers going to argue that Hitler didn't know about it, they need to provide that evidence - and not just vague waffle and photographs of Hitler with Jewish Children (2). Something along the lines of an entry in Himmler's diary, reading, "Ordered the liquidation of Europe's Jews. Must remember to not tell Adolf, the damn Jew-lover is such a softy" would suffice. But that has also proved elusive.
This is where the Holocaust denier's 'logic' turns against them. They maintain that the lack of a Furhrer order shows that the Holocaust happened (assuming they grant that much) without Hitler's knowledge or approval - but they have no evidence to support this contention. The Holocaust undoubtedly did happen - there is a wealth of evidence that testifies to that. Claiming it occurred without Hitler's approval is a remarkable claim, and - to quote the 'hard core disbeliever' (3), David Irving, if they are going to make that claim, "The ball is in their court" (4).
From this double standard we can learn a lot about the psychology and the aims of the Holocaust deniers. This is something that happens over and again in the dark world of denierist nonsense - something as strongly evidenced as tha organised and deliberate slaughter of six million people is questioned, but an absurd and unsubstantiated claim that it might have happened without Hitler's knowledge and approval is immediately accepted as valid, even if there is nothing to support it.
So we canb say, safely, that anyone who puts forward the argument that there is no Hitler Order is attempting to confuse the issue. It doesn't matter that there is no Hitler Order. There doesn't need to be one. The onus is on them to provide positive evidence that Hitler didn't know about the Holocaust.
1 - "The Plum Cake," by John Weir, published on the website of the Committee for Open Debate on the Holocaust, no date given. (http://www.codoh.com/revisionist/comment/tr08plumcake.html)
2 - Entry in David Irving's online journal, dated 29th of December, 2007. (http://www.fpp.co.uk/docs/Irving/RadDi/2007/301207.html).
3 - As described previously on lefthandpalm: http://lefthandpalm.blogspot.com/2009/01/david-irving-absolutely-stark-staring.html
4 - From "Introduction to The Leuchter Report," by David Irving, 1989. Reproduced on Irving's website (http://www.fpp.co.uk/Auschwitz/Leuchter/ReportIntro.html).