Fitzgerald, a Bush appointee who is the U.S. attorney in Chicago, issued a statement disputing the president's assertion that the sentence was "excessive," saying "an experienced federal judge" had followed the "applicable laws" in imposing punishment.
"It is fundamental to the rule of law that all citizens stand before the bar of justice as equals," he said. "That principle guided the judge during both the trial and the sentencing."
Libby's plight posed an acute political dilemma for Bush, who has shown reluctance to issue pardons but felt strong pressure to pardon Libby.
Bush has granted far fewer pardons than most presidents in the last 100 years, said Margaret Colgate Love, a former Justice Department attorney who oversaw pardons for eight years. Bush has issued only a third as many as pardons as President Reagan, for example, over the same duration in office.
Bush's public approval has sagged badly in the last two years. Many of his strongest supporters are conservatives who believe Libby should not have been prosecuted in the first place. They argue that Plame was not a true covert agent and that no crime was committed when her identity became public. And they note that others admitted to having revealed Plame's identity, including former Deputy Secretary of State Richard L. Armitage, whose conversation with columnist Robert Novak led to the first public mention of her.
House Judiciary Committee Chairman John Conyers Jr. (D-Mich.) said he planned to hold hearings on the administration's handling of the leak in the Plame case.
"Now that the White House can no longer argue that there is a pending criminal investigation, I expect them to be fully forthcoming," he said.
Wilson, in an interview with the Los Angeles Times, condemned the commutation and suggested that Bush was acting to ensure that full details of his or Cheney's involvement in the leak affair would never come to light. With Libby off the hook for any jail time, Wilson said, the former White House aide will have no incentive to cooperate with investigators in the future about involvement of his superiors.
"The president has clearly short-circuited the rule of law and the system of justice in this country, and I think there is a legitimate reason to ask why," Wilson said.
John J. Pitney Jr., a former Republican staffer who is a professor of politics at Claremont McKenna College, questioned whether Bush's decision would have much political effect. "Anybody who would disapprove of the commutation has turned against Bush already," he said.
Pardons and commutations
I. Lewis "Scooter" Libby is the fourth person to have a sentence commuted by President Bush. A commutation lessens the severity of the punishment for a crime but does not change the underlying conviction. A pardon forgives the offense itself. Here's a look at pardons and commutations of past presidents:
| Petitions | Pardons | Commutations | |
| received | granted | granted | |
| Harry S. Truman, 1945-53 | 5,030 | 1,913 | 118 |
| Dwight D. Eisenhower, 1953-1961 | 4,100 | 1,110 | 47 |
| John F. Kennedy, 1961-64 | 1,749 | 472 | 100 |
| Lyndon B. Johnson, 1964-1969 | 4,537 | 960 | 226 |
| Richard M. Nixon, 1969-1975 | 2,591 | 863 | 60 |
| Gerald E. Ford, 1975-77 | 1,527 | 382 | 22 |
| Jimmy Carter, 1977-1981 | 2,627 | 534 | 29 |
| Ronald Reagan, 1981-89 | 3,404 | 393 | 13 |
| George H.W. Bush, 1989-93 | 1,466 | 74 | 3 |
| William J. Clinton, 1993-2001 | 7,489 | 396 | 61 |
| George W. Bush, 2001-2007 | 9,000 | 113 | 4 |
Notable pardons and commutations
Nixon
Jimmy Hoffa: Teamster boss' 13-year sentence for jury tampering and mail fraud was commuted in 1972.
Ford
Nixon: Pardoned former president in 1974.
Tokyo Rose: American Iva Toguri, imprisoned for making treasonous radio broadcasts during World War II, was pardoned in one of Ford's final acts in office in January 1977.
Carter
G. Gordon Liddy: After refusing to testify in 1973 about the Watergate break-ins, Liddy served 4-1/2 years in prison; his sentence was commuted in 1977.
Patty Hearst: Heiress' sentence was commuted in 1979, after she served almost two years of a seven-year sentence on a federal bank robbery conviction. She was pardoned by Clinton in 2001.
Reagan
Maryland Gov. Marvin Mandel: Sentence of former governor was commuted in 1981, after he was jailed on mail fraud and racketeering charges.
George H.W. Bush
Caspar Weinberger: Reagan Defense secretary was pardoned in 1992 along with five other Reagan officials before the Iran-Contra trial.
Clinton
Roger Clinton: President's younger half-brother was pardoned for a 1985 drug-related offense.
Marc Rich: Billionaire fugitive financier was pardoned in the 11th hour in 2001.
Dan Rostenkowski: Illinois congressman convicted of mail fraud in 1996, was pardoned in 2000.
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Sources: U.S. Justice Department, Jurist Legal Intelligence, Times reporting.