WASHINGTON (AP) – At his sentencing Tuesday, former White House aide I. Lewis “Scooter” Libby will learn whether he will go to prison and, if so, whether it will be right away for his conviction in the CIA leak case.

Once Libby’s fate is known, then there is this ultimate question: Will President Bush pardon him?

Libby, the former chief of staff to Vice President Dick Cheney and assistant to Bush, was convicted in March of lying and obstructing the investigation into the 2003 outing of CIA officer Valerie Plame.

Special Prosecutor Patrick Fitzgerald is calling for Libby to spend up to three years in prison.

Libby maintains his innocence. With the support of several current and former White House, State Department and Pentagon officials, he has asked U.S. District Judge Reggie B. Walton, not to send him to prison.

Walton has a reputation as one of the district’s strictest judges.

Since Libby’s conviction, the White House has sidestepped talk of pardoning Libby. Some of Libby’s supporters have spoken publicly about a pardon, while Democrats are asking Bush to promise not to issue one.

Bush said he is “pretty much going to stay out of” the case until the legal fight is over.

That becomes harder to do if Walton sends Libby to prison. Bush will have to decide whether to pardon his former aide or let him serve his time.

“If jail time is issued, I would hope the president would issue a pardon,” said former Sen. Don Nickles, R-Okla., a member of Libby’s legal defense fund.

A pardon decision could be delayed, however, if Walton sentences Libby to prison but puts the sentence on hold. Normally, defendants are ordered to report to prison within weeks. But the law allows – and defense lawyers said they will ask – Walton to delay the sentence until appeals have run out.

That could be many months, at the earliest, or even more than a year.

Libby’s lawyers say he should be given leniency because of his lengthy career in public service. They also note that nobody was charged with leaking Plame’s identity and suggest that Libby should not be punished as if he was a leaker.

“There is no evidence in the record here to support a finding that any underlying offense was actually committed by Mr. Libby or anyone else,” his lawyers wrote.

It is a common refrain in perjury cases, and one that points up a Washington truism: It usually is the cover-up that gets people in trouble.

During the scandal that led to President Clinton’s impeachment, while Democrats decried Independent Counsel Kenneth Starr’s investigation as politics run amok, Republicans fell back on a familiar ground:

“This case is not about sex,” Nickles said in 1998. “This case is about perjury.”

Now Nickles and Libby’s other supporters find themselves on the other side, railing against Fitzgerald’s investigation.

“I think he became so wrapped up in the case, he lost perspective and said, “I gotta get something for this. I gotta get a scalp,” Nickles said recently.

Fitzgerald knew early on that Libby was not the source of the newspaper article that first identified Plame, the wife of an outspoken war critic. But the prosecutor said he needed to know whether others in the government authorized that leak and he referred in court to “a cloud” over Cheney.

“In short, Mr. Libby lied about nearly everything that mattered,” Fitzgerald said in court documents.

Nickles said it was unfair to draw comparisons with Clinton’s scandal, which was “a different level of intensity.” Nickles noted that Clinton was not convicted by the Senate and was spared prosecution in civilian court.

It’s also hard to compare Libby’s case with other politically charged trials.

Dwight L. Chapin, an aide to President Nixon, was convicted of two counts of perjury in 1973 and served six months in prison for lying to a federal grand jury investigating the Watergate scandal. Unlike Libby, Chapin was not convicted of obstruction.

Nixon’s domestic affairs adviser, John D. Ehrlichman, and chief of staff, H.R. Haldeman, served 18 months of a four-year to eight-year term for obstruction of justice, conspiracy and perjury. Libby, however, was not charged with conspiracy.

Domestic diva Martha Stewart, whose 2004 trial was far less political but no less publicized, was sentenced to five months prison for conspiracy, obstruction and making false statements for lying to investigators about a stock sale.

Walton, who was nominated to the bench by Bush, has offered few clues about what type of sentence he is leaning toward.

In a ruling last week, however, he indicated he did not view the conviction lightly. He received more than 150 letters in the case, which he said was evidence of the public’s interest in the case and “the weightiness of the underlying charges.”

AP-ES-06-02-07 1231EDT