HAd Lincoln or FDR survived their wars, or Nixon not resigned for other matters, then we might have some precedent for placing POTUS on trial for war time decisions, as is we have a precedent for not doing it. We also have a precedent for leaving the former president be, which survived Clinton's impeachment, purgery, disbarrment, and refusal to disappear from the public light. They talked about putting him on trial too, Bush told them to drop it. Obama will undoubtedly do the same, and if he doesn't it will only reinforce his growing image of blaming Bush for everything, which is wearing increasingly thin. If Bush were put on trial, everyone would see Obama as the driving force, and it will be viewed by most people as petty vindicative behavior