So their Cunning Plan is for Bush to pardon everybody in sight before handing over the White House keys and the TV remote. The pardon power looks absolute in US law, though its abuse could be impeachable. So pardons would pre-empt any proceedings other than impeachment for violations of US law.
I have an even more Cunning Plan. President Obama and the Senate ratify the Rome Statute of the International Criminal Court. The United States then invites the ICC prosecutor, Luis Moreno-Ocampo, to investigate possible war crimes falling under Bush’s pardons, under the international criminal law codified in the Statute. The case would be admissible under Article 17.1(a), since the USA would be
unable genuinely to carry out the investigation or prosecution.
(The French text is “dans l’incapacité de mener véritablement à bien l’enquête ou les poursuites“; the English adverb would better be properly.)
Have a look at Articles 27, 28, and 33: Presidents, Vice-Presidents, Chiefs of Staff, and subordinates “just obeying orders” are explicitly not exempt from prosecution. Under Article 54, the Prosecutor could investigate on US territory and seek the assistance of its authorities to question witnesses. If the Court issued an arrest warrant, the United States would be required under Article 59 to
immediately take steps to arrest the person in question.
It ain’t over till the fat lady sings.