No one has mentioned that Bush does have a solution to his Scooter pardon problem. It would appease the right without infuriating the left. There is a third option between doing nothing and issuing a pardon. Unfortunately it could reduce the political heat.
At the moment the right is particularly hot and bothered about the severity of the sentence. Given the anger of his base over the immigration issue, Bush might need to appease them. A pardon would certainly do that, but it would provoke a firestorm from the Left. That is opposition that he would not mind since, reactively, it would rally the Limbaugh base to his cause, but it would reveal once again the hypocrisy of his policies, perhaps even provoking Broder and the Washington Post editorial board. None of this is a major consideration given his indifference to public opinion, but he would prefer to avoid yet another problem
Assuming as now seems likely that Judge Walton will insist that Libby start his sentence before appeals are exhausted, Libby will make his final move from the White House to the big house in about two months. At that point Bush does have a way-station on the way to pardon. He can simply commute the sentence so that Libby need serve no time. Commutation of a sentence is not a pardon and would not, I believe, be subject to the same high procedural standards. Libby would still be a felon, subject to all its moral and legal consequences, but he would be out of jail. At that point pressure from the right for the politically more fraught pardon would diminish. If Bush is still inclined in that direction, he could pardon him just before leaving office.