Via email from his spokesperson:
We fully recognize that the Constitution provides that commutation decisions are a matter of presidential prerogative and we do not comment on the exercise of that prerogative.
We comment only on the statement in which the President termed the sentence imposed by the judge as “excessive.” The sentence in this case was imposed pursuant to the laws governing sentencings which occur every day throughout this country. In this case, an experienced federal judge considered extensive argument from the parties and then imposed a sentence consistent with the applicable laws. It is fundamental to the rule of law that all citizens stand before the bar of justice as equals. That principle guided the judge during both the trial and the sentencing.
Although the President’s decision eliminates Mr. Libby’s sentence of imprisonment, Mr. Libby remains convicted by a jury of serious felonies, and we will continue to seek to preserve those convictions through the appeals process.
For the record, when I said almost the same thing on Hardball, I hadn't gotten this yet in the email. Glad to see that my feeble mind is thinking along the lines of a great mind.
Update: Oh wait, I think I said the bit about the fact that this was not an excessive sentence for a different interview, that will no doubt be cut. You'll have to take my word for it then.