Former White House aide Lewis "Scooter" Libby has been jailed for two-and-a-half years for lying and obstructing an investigation over the administration's handling of the Iraq war.
Libby, former Chief of Staff to US Vice President Dick Cheney, arrives for his sentencing hearing at US District Court in Washington today
Investigators were trying to determine who leaked the identity of CIA analyst Valerie Plame in 2003 after husband accused the Bush administration of manipulating intelligence to build its case for war.
US District Court Judge Reggie Walton also imposed a fine of $250,000 and two years probation. Libby's lawyers were expected to ask Judge Walton to suspend the sentence while they appeal the case.
Observers say he might never go to jail thanks to a lengthy appeals process and a possible pardon from President Bush.
Dozens of prominent people — including former Defence Secretary Donald Rumsfeld, Marine General Peter Pace, chairman of the Joint Chiefs of Staff, former Secretary of State Henry Kissinger, and John Bolton, former US ambassador to the United Nations — wrote letters to the judge in support of Libby's bid for probation.
Mr Rumsfeld wrote: "My hope and prayer is that his outstanding record, his many contributions to our country and his value as a citizen will be considered carefully."
The prosecutor in the case, Patrick Fitzgerald, asked Judge Walton to impose a sentence of two-and-a-half to three years; the federal probation office recommended less than two years.
Libby's charges grew out of a high-profile investigation into the leak of a CIA analyst's identity after her husband emerged as an early critic of the invasion of Iraq.
CIA analyst Valerie Plame has testified that the unmasking destroyed her career.
Nobody was charged with blowing her cover, but Libby, Mr Cheney's former chief of staff, was found guilty of obstruction of justice, making false statements to the FBI and two counts of perjury. He was found not guilty of one charge of making false statements.
Libby was one of several Bush administration officials who discussed Ms Plame with reporters at a time when her employment status was classified.