It's right there in Steven Bradbury's memo of May 30, 2005:
By its terms, Article 16 [of the United Nations Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment of Punishment] is limited to conduct within "territory under [United States] jurisdiction. We conclude that territory under United States jurisdiction includes, at most, areas over which the United States exercises at least de facto authority as the government. Based on CIA assurances, we understand that the interrogations do not take place in any such areas.
So no torture happened and the US broke no treaties.
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