Manfred Nowak, the UN's special rapporteur on torture, called on the US authorities to pursue the former president and his former defence secretary for the treatment of prisoners held at the Guantanamo Bay camp in Cuba.
"Judicially speaking, the United States has a clear obligation," he told German television.
He said that the US had ratified the UN convention on torture which requires "all means, particularly penal law" to be used to bring proceedings against those violating it.
"We have all these documents that are now publicly available that prove that these methods of interrogation were intentionally ordered by Rumsfeld," Mr Nowak claimed.
"But obviously the highest authorities in the United States were aware of this."
No trips out of the country for Bush, or Rummy, or Cheney, not that they'd want to go.