Arendt is at pains to explain that this book was just a trial report and she is further at pains to dispel the idea of controversy that seems to surround it. There are certain points continually broached by the author and they are that 1) the trial was a foregone conclusion and the manner in which it was conducted never addressed the principal charges 2) Eichmann was at no time much more than a glorified clerk (nowhere more evident than in his role at the wanasee conference) 3) Eichmann never killed anyone 4) the trial raised questions of humanity, not just of Eichmann or Germany or the SS or the Holocaust 5) was Israel the apropriate place for this trial?
What seems to have created the controversy was mostly the study of Eichmann that Arendt made (point 2). Eichmann continually stressed that he was not a 'Jew-hater', in fact he reports repeatedly of his contact with and respect for the Zionists. In fact, Eichmann also stresses that he never killed anyone nor was he ever capable of it.
So what is Arendt saying? well, she is actually just making a report, not really a judgement. She never suggests for a moment that Eichmann is not guilty of some definition of crimes against humanity - he shipped hundreds of thousands of Jews to their deaths. But what of the machine of government? Actually, she is not telling us that we might have been Eichmann under the same circumstances and she is not justifying his behaviour thus. There is no contention that his defence of 'i followed orders' is in anyway suitable to explain his crimes. But, Eichmann is no monster and that's not what people want to hear about the so-called 'architect of the Final Solution'.
The wider question of whether or not the court of an individual country can, or should, judge crimes against humanity in general is not one she particularly cares to answer, but i think history has done that for her.
An excellent, disturbing and utterly stimulating read for any student of WWII and/or the Holocaust.