Obama is musing about extending the political reach of the criminal law. If he does so, he will find he has opened a new front of political warfare that will not soon end.
After the 9/11 attacks, President Bush drew a curtain of oblivion against all the errors and mistakes that had led up to the attacks. There was accusation and counter-accusation in the media, but at the official level there was no recrimination against President Clinton's decision not to kill bin Laden when he had the chance, no action against those who had failed to stop the 9/11 hijackers from entering the country.
If Obama proceeds to take legal action against those who did what they thought was right to defend the country, all that will change. Prosecutions launched by Obama will not stop when Obama declares "game over." If overzealousness under Bush becomes a crime under Obama, underzealousness under Obama will become a crime under the next Republican president.
At least until now, the U.S. political system has avoided the spectacle of a new Administration prosecuting its predecessor for policy disagreements. This is what happens in Argentina, Malaysia or Peru, countries where the law is treated merely as an extension of political power.