President Obama [has thus far] failed to bring to justice anyone responsible for the ... official government [torture] program conceived and carried out in the years after the attacks of Sept. 11, 2001. He did allow his Justice Department to investigate the C.I.A.'s destruction of videotapes of torture sessions and those who may have gone beyond the torture techniques authorized by President George W. Bush. But the investigation did not lead to any charges being filed. The American Civil Liberties Union and Human Rights Watch are ... calling for appointment of a special prosecutor to investigate what appears increasingly to be "a vast criminal conspiracy, under color of law, to commit torture and other serious crimes." The question everyone will want answered, of course, is: Who should be held accountable? Any credible investigation should include former Vice President Dick Cheney; Mr. Cheney's chief of staff, David Addington; the former C.I.A. director George Tenet; and John Yoo and Jay Bybee, the Office of Legal Counsel lawyers who drafted what became known as the torture memos. There are many more names that could be considered. Because of the Senate's report, we now know the distance officials in the executive branch went to rationalize, and conceal, the crimes they wanted to commit. The question is whether the nation will stand by and allow the perpetrators of torture to have perpetual immunity for their actions.