From the Wall Street Journal’s Law Blog: A Law Professor’s Inside Take on Bush’s Commutation Policy:
Judge Gonzales told me three things about President Bush’s policy in considering requests for commutation. First, that President Bush would not consider commutation if he believed that the case had already received full and fair consideration by the jury and the courts who heard the case. Second, that the President would not consider the request until he had a recommendation from the Department of Justice. Finally, he said that the President would not act on any request for commutation until all judicial avenues in the case had been exhausted.
The whole thing is worth reading.