The prosecutor is often first presented with a case as a "corpus delicti" — a bullet-riddled body in the street, for instance. That ordinarily is enough to justify investigation. Through investigation, the evidence may prove that there was not in fact a crime (it was a suicide or an accident) or that the fatal acts were privileged or enjoy a legal defense (self-defense or justifiable shooting by an officer of the law). But one begins by investigation.

The judicial branch (which, under Marbury v. Madison, has the ultimate duty to determine "what the law is") has determined that waterboarding is torture (see U.S. v. Lee, decided in 1984 by the U.S. Court of Appeals for the 5th Circuit). The Bush administration has admitted to waterboarding captives. The corpus delicti of that crime exists. For there to be investigation now is unexceptional.

The only exceptional thing is the parties involved: the former vice president of the United States, his counsel David Addington, Office of Legal Counsel (OLC) lawyer John Yoo and their private contractors Bruce Jessen and Jim Mitchell, psychologists who designed the torture program. But in America, high office does not put one outside the law. Indeed, it borders on unethical for a prosecutor to refuse to investigate the corpus delicti of a crime because of concern as to where the evidence may lead.

With the corpus delicti present, a prosecutor looks to see whether theories of criminal liability can be eliminated by evidence the investigation reveals (a suicide note in the pocket, a police officer's convincing description of a "clean shoot"). But as long as a viable theory of criminal liability remains, the investigation continues.

Hence the question: Looking only at the evidence that has become public so far, is there a viable theory of criminal liability arising out of this corpus delicti, the torture of America's captives?