Commuting the sentence is a brilliant strategy.
If Bush had pardoned Libby, the whole case is closed. With Libby still able to appeal, it keeps the pressure on Fitzie and NBC and the Wilsons. We want to know what Andrea Mitchell knew. We want to know why Fitz kept the truth secret for so long. We want an appeals trial so the truth comes out. This can only happen if the case is kept alive. And since Libby is no longer fighting to keep is life intact, he can afford to come out all guns blazing.
See my post #608. I am quite confident that any brilliance attained by this administration is purely accidental.