I'm reposting this 7 February 2002 memo, signed by Bush. (Source: this archive, which I discovered via this dKos diary.)
The central finding of the memo is that members of AQ are not covered under either article 3 or 4 of the Geneva Conventions. Accordingly, "detainees" held to be members of AQ need be "treated in a manner consistent with the principles of Geneva" only insofar as is "appropriate and consistent with military necessity". In other words, torture away.
The central finding is clearly false. According to convention IV, part 1, article 4, paragraph 4:
Every person in enemy hands must have some status under international law: he is either a prisoner of war and, as such, covered by the Third Convention, a civilian covered by the Fourth Convention, or again, a member of the medical personnel of the armed forces who is covered by the First Convention. There is no intermediate status; nobody in enemy hands can be outside the law.
There you have it, war crimes approved by Bush's hand.