1. Each State Party shall take effective legislative, administrative, judicial or other measures to prevent acts of torture in any territory under its jurisdiction.
2. No exceptional circumstances whatsoever, whether a state of war or a threat or war, internal political instability or any other public emergency, may be invoked as a justification of torture.
3. An order from a superior officer or a public authority may not be invoked as a justification of torture.
United Nations Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment
(Photo: An Abu Ghraib detainee who was beaten to death whilst in a 'stress position')
[Update: Rhodo Zeb has a solid round-up of the legal debate - as much as there is anything debatable about torture - over on his blog]