I am not sure I disagree with the implications of colleague Phillip Carter's note about the next administration undertaking a war crimes investigation of the incumbent, but were the question put directly: Should President Obama launch yet another legal investigation into the alleged war crimes of the Bush administration?
The answer -- absent clear evidence of a criminal intent to subvert the law well beyond what even the most severe Bush critic alleges -- is "no." That seems to be the answer Senator Obama wisely supplied.
Far more important for the United States is having a president who will observe the scope of the presidential office, the rule of law as written, and who reaffirms what the international community has already said - water-boarding is torture. In a perfect world, it would've been nice if the Office of Legal Counsel had said all that at the beginning, but it didn't, and it is perfectly understandable why an intelligent man like Attorney General Mukasey has wanted to get on to other things. All of the prudence in the world commends the next president to do the same.
Of course, it is important to ensure that objective legal advice will again be given the next Attorney General by the Office of Legal Counsel, and the best way to ensure that is by appointing a person of independence and stature to that position. Harvard's Laurence Tribe, Columbia's Thomas Merrill, Northwestern's John McGinnis, and UC Davis' Vik Amar readily come to mind from academic ranks. And there are multiple possibilities from among appellate judges: Merrick Garland of the D.C. Circuit and Mike McConnell of the Tenth Circuit just to give two obvious examples appointed by different presidents of different political parties.
The point is: integrity is not a partisan commodity and the giving of objective legal advice more often than not depends upon that quality being freely mixed with a level of maturity that has seen history repeat itself and the courage, when warranted, to say "no."