Does the President have unlimited power to commute a sentence or to pardon?

I had always understood that the President can commute a sentence or pardon anyone for any reason, but there may be limits.

Dan Froomkin, who blogs for the Washington Post at White House Watch, devoted yesterday’s long post to Bush’s commutation of Libby’s sentence, available here.

Excerpt: “It's true that the Constitution grants the president unlimited clemency and pardon power. But presidents have generally used that power to show mercy or, in rare cases, make political amends -- not to protect themselves from exposure.

“The Framers, ever sensitive to the need for checks and balances, recognized the potential for abuse of the pardon power. According to a Judiciary Committee report drafted in the aftermath of the Watergate crisis: ‘In the [Constitutional] convention George Mason argued that the President might use his pardoning power to 'pardon crimes which were advised by himself' or, before indictment or conviction, 'to stop inquiry and prevent detection.' James Madison responded:

"[I]f the President be connected, in any suspicious manner, with any person, and there be grounds [to] believe he will shelter him, the House of Representatives can impeach him; they can remove him if found guilty. . . .

"Madison went on to [say] contrary to his position in the Philadelphia convention, that the President could be suspended when suspected, and his powers would devolve on the Vice President, who could likewise be suspended until impeached and convicted, if he were also suspected."

Scott Horton, who blogs for Harper’s Magazine at No Comment, added his comments about the President’s powers to relieve a convicted person of his/her sentence to Froomkin’s here. Excerpt: "Certainly the Constitution vests the president with plenary power to pardon, so the wielding of that power is Constitutionally protected. The exception perhaps is quite narrow: what about the case when the power is invoked to protect the president himself from a criminal investigation or potential prosecution. Is it absurd to suspect that this is what’s going on here? It’s premature to draw conclusions, but certainly there are grounds for this suspicion. But to be more precise, the suspicion is that the president is using the pardon power to protect the vice president from a criminal prosecution." [bolding mine]

Sidebar: According to this morning’s New York Times, Bush Rationale on Libby Stirs Legal Debate, quoting former Alabama governor Don Siegelman’s lawyer, Susan James, “The Libby clemency will be the basis for many legal arguments,” James is handling the appeal of the sentence he received last week of 88 months for obstruction of justice and other offenses.

“It’s far more important than if he’d just pardoned Libby,” Ms. James said, as forgiving a given offense as an act of executive grace would have had only political repercussions. “What you’re going to see is people like me quoting President Bush in every pleading that comes across every federal judge’s desk.”

I hope Siegelman succeeds. His recent sentence prompted me to post Where is the outrage?

(Cartoon: Tom Toles, Washington Post – July 4, 2007)