In his 2007 confirmation hearing before the Senate Judiciary Committee considering his nomination to be Attorney General of the United States, Judge Michael Mukasey refused to address the legality of waterboarding. In my opinion there is no reasonable dispute about this matter. The laws of the United States make waterboarding unlawful in no uncertain terms.
Slip Opinions: The online supplement to Washington University Law Review
Wilson R. Huhn, Waterboarding is Illegal, Slip Opinions: The online supplement to Washington University Law Review (2008).