In his commentary, Greenwald points out that a 2002 Justice Department memorandum primarily written by Assistant Attorney General John Yoo redefined "torture" as "the pain accompanying serious physical injury, such as organ failure, impairment of bodily function, or even death."
The memorandum made actions that had been taken against prisoners at Guantanamo "perfectly legal," and the follow-up Military Commissions Act of 2006 wrote the policy into federal law.
The article also mentions that Attorney General candidates Alberto Gonzales and his successor Michael Mukasey both said at their confirmation hearings that they would prosecute pornography in response to questions by Senators Sam Brownback (R.-Kan.) and Orrin Hatch (R-Utah).
Greenwald's article, "Porn Producer Invokes the Bush/Yoo Defense — Unsuccessfully" can be accessed here.