It would be easy to make the entire book into a debate about Slahi's involvement in the 9/11 attacks or with Al-Qa'eda. Of course in his version of the story, he is seriously uninvolved, which is part of the reason that in 14 years of torture, they could never convict him of war crimes—but all that is moot, because as the torturing itself proved, no one will know the truth about Slahi's potential involvement, but one this is extremely clear from this story: The US government tortured plenty of people following 9/11, without due process, keeping them in jail for decades without charges or trial.
To focus on 9/11 itself would be to miss the core argument of the story, which is that the due process of US law should protect every human, especially the presumption of innocence. In US law, a person accused of a crime has rights afforded to them, not based in citizenship, but based in the divine autonomy of the individual, in their sovereign value as a human being.
It's on these bases that the US government is legally bound to give every alleged criminal a criminal proceeding to determine their guilt, and to punish only in ways that are never "cruel or unusual." The torture of Slahi was cruel and unusual in ways so extreme that he is literally not at liberty to tell the audience because the US government censored the autobiography before it was published.
Slahi's point of view is crucial, because it serves as a counterpoint to the common argument that the US government should do whatever they can to protect their citizens. Slahi's unimaginable, horrific treatment is a reminder that our safety can be secured in ways that are less than ethical (to say the absolute least on the issue).
