May 25 (Bloomberg) -- Former vice presidential aide I. Lewis Libby should go to prison for up to three years because he ``lied repeatedly and blatantly'' to obstruct a probe into the leak of a covert CIA official's identity, a prosecutor told a U.S. judge.

Prosecutor Patrick Fitzgerald said in court papers that Libby, who was Vice President Dick Cheney's chief of staff, deserves imprisonment for 30 to 37 months. Libby was convicted March 6 of obstructing justice, making false statements and two counts of perjury.

``Mr. Libby, a high-ranking public official and experienced lawyer, lied repeatedly and blatantly about matters at the heart of a criminal investigation,'' Fitzgerald said in court papers. ``He has shown no regret for his actions, which significantly impeded the investigation.''

Libby, 56, is scheduled to be sentenced June 5 by U.S. District Judge Reggie Walton in Washington.

Fitzgerald, the U.S. attorney in Chicago, was appointed a special prosecutor to determine who leaked the identity of CIA official Valerie Plame to journalists after her husband, a critic of President George W. Bush's Iraq war policy, questioned intelligence the president cited to justify the 2003 invasion.

Cheney spokeswoman Lea Anne McBride declined to comment on the sentencing recommendation. ``It's a matter before the courts,'' she said. Libby's lawyer, Theodore Wells, didn't immediately respond to requests for comment.

`Substantial Time'

Fitzgerald wrote that Libby's lies to FBI agents and a federal grand jury forced prosecutors ``to expend substantial time and resources'' to complete their investigation after quickly determining that three Bush administration officials disclosed Plame's identity as a CIA agent to reporters.

Investigators wanted to determine if the disclosures by Libby; Karl Rove, Bush's top political adviser, and Richard Armitage, then deputy secretary of state, had been ``deliberate, reckless or inadvertent'' and whether they were authorized by others, Fitzgerald said.

The investigation forced journalists to disclose their sources and others to reveal ``sensitive personal information,'' Fitzgerald said.

Witnesses who told the truth ``risked the possibility of criminal prosecution, or personal or political embarrassment,'' Fitzgerald said.

``Regrettably, Mr. Libby chose the one option that the law prohibited: he lied,'' Fitzgerald wrote in the sentencing memo. ``He lied about multiple facts central to an assessment of his role in the disclosure of Ms. Wilson's CIA employment.''

Neither Rove nor Armitage was charged in the investigation.

Column by Novak

Plame's name was first published by syndicated columnist Robert Novak eight days after Plame's husband, Joseph Wilson, had written a July 6, 2003, column for the New York Times challenging Bush's assertion in his State of the Union address that Iraq may have tried to buy uranium to build a nuclear weapon.

The CIA had sent Wilson to the African nation of Niger to verify the British intelligence report. Wilson wrote that he found no evidence to support the claim that agents for Iraqi leader Saddam Hussein tried to buy uranium ``yellowcake'' in Africa.

Evidence at the trial showed that in conversations at the White House, Libby and other aides were upset about Wilson's criticism. Libby first learned about Plame's identity from Cheney, who suggested in handwritten notes that she had arranged a ``junket'' for her husband.

Fitzgerald asked the judge to disregard statements made by friends and supporters to the probation officer that Libby's public service should excuse him from imprisonment and that his prosecution was unwarranted and politically motivated.

``Mr. Libby's prosecution was based not upon politics but upon his own conduct, as well as upon a principle fundamental to preserving our judicial system's independence from politics,'' Fitzgerald wrote. ``The judicial system has not corruptly mistreated Mr. Libby,'' who a jury found ``to have corrupted the judicial system.''

To contact the reporter on this story: James Rowley in Washington at jarowley@bloomberg.net

Last Updated: May 25, 2007 17:28 EDT