Vice President Dick Cheney's chief aide I. Lewis "Scooter" Libby (search) was indicted Friday as a result of the investigation into the leak of CIA operative Valerie Plame Wilson's identity to reporters two years ago.

Despite Special Counsel Patrick Fitzgerald (search) saying that Libby actively misled investigators and the grand jury, Libby said he believed his innocence will prevail.

"I am confident that at the end of this process I will be completely and totally exonerated," Libby said through his lawyer, Joseph Tate.

Karl Rove (search ), President Bush's top political aide, was spared from criminal charges on Friday, but the possibility remained that he could be charged later. Fitzgerald said the bulk of the work is concluded and the grand jury has expired but the investigation is not over.

Fitzgerald also told reporters in an afternoon press conference at the Justice Department that "at the end of the day what appears is that Mr. Libby's story that he was at the tail end of a chain of phone calls, passing on from one reporter what he heard from another, was not true. It was false.

"It would be a compelling story that will lead the FBI to go away if only it were true. It is not true, according to the indictment," he said.

The 22-page indictment alleges Libby committed five crimes — one count of obstruction of justice of the federal grand jury, two counts of perjury and two counts of false statements.

• Click here to view the indictment. (pdf)

Libby stepped down as Cheney's chief of staff just minutes after the indictment was handed down. A replacement could be named as early as Saturday.

"Today I accepted the resignation of Scooter Libby. Scooter has worked tirelessly on behalf of the American people and sacrificed much in the service to this country. He served the vice president and me through extraordinary times in our nation's history," Bush said before leaving the White House for Camp David for the weekend.

"Special Counsel Fitzgerald's investigation and ongoing legal proceedings are serious and now the process moves into a new phase. In our system, each individual is presumed innocent and entitled to due process and a fair trial," Bush said.

Cheney also expressed regret for Libby's resignation.

"Mr. Libby has informed me that he is resigning to fight the charges brought against him. I have accepted his decision with deep regret. Scooter Libby is one of the most capable and talented individuals I have ever known. He has given many years of his life to public service and has served our nation tirelessly and with great distinction," the vice president said, adding that he would not comment further on a pending case.

According to a summary of the indictment issued by the prosecutor's office, Libby was indicted for "allegedly lying about how and when in 2003 he learned and subsequently disclosed to reporters then-classified information concerning the employment of Valerie Wilson by the Central Intelligence Agency."

"The charges allege that Libby lied to FBI agents who interviewed him on Oct. 14 and Nov. 26, 2003; committed perjury while testifying under oath before the grand jury on March 5 and March 24, 2004; and engaged in obstruction of justice by impeding the grand jury’s investigation into the unauthorized disclosure – or 'leaking' – of Valerie Wilson’s affiliation with the CIA to various reporters in the spring of 2003."

A guilty verdict could mean a maximum 30-year jail sentence and $1.25 million in fines. Federal prison has no parole. However the odds are low that Libby, who has no prior record and who has years of public service, would be given a maximum sentence if convicted.

The charges are based on the assertion that Libby was not forthcoming with the grand jury or the FBI when questioned about when he first learned the identity of CIA operative Wilson, also known as Valerie Plame (search).

Part of the indictment focuses on Libby's alleged deception about conversations he had with Time magazine reporter Matt Cooper (search), New York Times reporter Judith Miller (search) and TV's "Meet the Press" host Tim Russert. According to the indictment, in those conversations Libby allegedly confirmed Plame's identity to Miller and Cooper, rather than learning her name from them. The indictment also says Russert and Libby never discussed Plame.

Libby's own notes show that he learned Plame's identity from his boss, the indictment contends.

Democrats were quick to react to the news of the indictment.

"The criminal indictments of a top White House official mark a sad day for America and another chapter in the Republicans' culture of corruption. At the heart of these indictments was the effort by the Bush Administration to discredit critics of its Iraq policy with reckless disregard for national security and the public trust," said House Minority Leader Nancy Pelosi of California.

"This case is bigger than the leak of highly classified information. It is about how the Bush White House manufactured and manipulated intelligence in order to bolster its case for the war in Iraq and to discredit anyone who dared to challenge the president," Senate Minority Leader Harry Reid of Nevada said in a statement.

Some Republicans also tried to distance themselves, though many said Libby is presumed innocent until proven otherwise.

"It's time to stop the leaks and spin and turn Washington into one big recovery meeting where people say what they mean and mean what they say," said Rep. Jim Ramstad, R-Minn.

Senate Majority Leader Bill Frist, R-Tenn., said through a spokesman that the Senate won't investigate the CIA leak.

Columnist Robert Novak (search) first revealed Plame's name and her CIA status in the press on July 14, 2003. That was five days after Novak talked to Rove and eight days after Plame's husband, former ambassador Joseph Wilson (search), published an opinion article in the Times accusing the Bush administration of twisting intelligence to exaggerate the threat posed by Iraq.

Wilson and his supporters have charged the leak of Plame's name, which ended her ability to work undercover for the CIA, was designed to discredit him and punish him for his criticism and intimidate others inside the government critical of Bush's Iraq policies.

Also in the backdrop of Fitzgerald's investigation is a set of forged documents that stated Iraq was acquiring uranium yellowcake from the African nation of Niger (search). Wilson had been sent by the CIA to Africa to investigate such reports, later used by Bush to help justify the war in Iraq.

Wilson issued a statement saying he was pleased with Fitzgerald's investigation.

"Today is a sad day for America. When an indictment is delivered at the front door of the White House, the Office of the President is defiled. No citizen can take pleasure from that," says the statement read by Wilson attorney Christopher Wolf.

"The five-count indictment issued by the grand jury today is an important step in the criminal justice process that began more than two years ago. I commend Special Counsel Patrick Fitzgerald for his professionalism, for his diligence, and for his courage," Wolf said.

The charges do not implicate Libby in the original cause for convening the grand jury — that someone in the White House knowingly and deliberately revealed a covert intelligence officer's identity. Tate, Libby's attorney, singled out the fact as cause for concern.

"To say we are disappointed is an understatement. Mr. Libby testified to the best of his honest recollection on all occasions. Mr. Libby cooperated fully with this investigation," Tate said in a statement.

Tate raised the question of whether Libby correctly remembered the events months after they happened, especially "in the hectic rush of issues and events at a busy time for our government."

"To be clear, Mr. Libby is innocent of these charges. We ask that you not judge this case until the verdict is in," Tate said.

Without discussing details, Fitzgerald said he would not confirm that Plame was a covert officer at the time her identity was revealed nor was Libby or others being charged for violating the Intelligence Identities Protection Act.

"We have not made any allegation that Mr. Libby knowingly or intentionally outed a covert agent. We have not charged that. And so I am not making that assertion," he said.

Fitzgerald did say that Valerie Plame's covert status was "blown" as a result of Libby's discussions. He added that "investigators do not set out to investigate the statute, they set out to gather the facts.

"It's critical that when an investigation is conducted by prosecutors, agents and a grand jury they learn who, what, when, where and why. And then they decide, based upon accurate facts, whether a crime has been committed, who has committed the crime, whether you can prove the crime and whether the crime should be charged," he said.

"In July 2003, the fact that Valerie Wilson was a CIA officer was classified. Not only was it classified, but it was not widely known outside the intelligence community. Valerie Wilson's friends, neighbors, college classmates had no idea she had another life," he added.

Prior to the indictment, Cheney arrived at the White House at 6:25 a.m., more than an hour earlier than usual. He then traveled to Georgia to deliver three speeches. His chief of staff left home about 6:15 a.m., his normal commuting time, and was at the White House in the morning before departing following his resignation.

Libby, 55, was Cheney's right hand man, a powerful position in a White House where the vice president has had unprecedented power. A trial could provide the public with details about the White House's thinking as it prepared for war in Iraq.

The indictment was approved by a majority of the 18-member grand jury. While their identities are sealed, the majority of jurors were black and the majority were women, including the foreperson.

The indictment was signed by Judge James Robertson in a procedure that lasted about five minutes. Fitzgerald did not present indictment papers to judge, but let two fellow prosecutors address the judge.

Once Robertson signed the indictment, the papers were walked down to the clerk's office, where it was formally processed and the a computer randomly assigned Judge Reggie B. Walton to be the trial judge. Walton is known among defense attorneys in Washington as a tough judge. Fitzgerald said Libby would not be arrested by police officers, but is expected to turn himself in to appear before Walton for arraignment.

While Rove is off the hook for now, his legal problems have not ended. He failed initially to disclose to prosecutors a conversation in which he told Time reporter Cooper that Plame worked for the CIA. The president's top political adviser says the conversation slipped his mind.

Reports have indicated that Fitzgerald would keep Rove under investigation. Sources close to Rove told FOX News that Fitzgerald decided not to prosecute Rove because Rove attorney Bob Luskin earlier this week offered information and an explanation that satisfied Fitzgerald enough to hold off on an indictment. While details were not available about the conversation, sources said Fitzgerald told Luskin he would continue to look into the matter with full consideration of Luskin's additional information and explanation.

"The special counsel has advised Mr. Rove that he has made no decision about whether or not to bring charges, and that Mr. Rove's status has not changed. Mr. Rove will continue to cooperate fully with the special counsel's efforts to complete the investigation. We are confident that when the special counsel finishes his work, he will conclude that Mr. Rove has done nothing wrong," Luskin said in a statement released Friday after getting approval from Fitzgerald to release the pre-emptive statement.

FOX News' Carl Cameron, Megyn Kendall and The Associated Press contributed to this report.