Confused about the CIA leak case? Start here.

For almost two years, Special Counsel Patrick Fitzgerald has led an investigation to determine whether anyone acted illegally when the identity of CIA agent Valerie Plame was made public. After hearing testimony from some of Washington's most powerful figures, a grand jury is expected to issue indictments as soon as Friday. The Monitor's White House correspondent, Linda Feldmann, answers key questions about the case. [Editor's note: The original version misidentified Patrick Fitzgerald's official title.]

Q. How did this affair begin?

At its heart lie questions about the Bush administration's case for war against Iraq. On Jan. 28, 2003, in his State of the Union address, President Bush included these 16 words: "The British government has learned that Saddam Hussein recently sought significant quantities of uranium from Africa."

The implication was that Iraq was developing a nuclear-weapons program. But US intelligence officials had by then - and have since - expressed doubts about that claim. In July 2003, Joseph Wilson, a former ambassador to two African countries and Iraq, wrote an op-ed in The New York Times disputing Mr. Bush's statement.

The CIA, he wrote, sent him to Niger in 2002 to determine if Iraq had tried to buy uranium from Africa. He concluded no. One week after Mr. Wilson's op-ed, syndicated columnist Robert Novak reported that Wilson's wife, Valerie Plame, worked as "an Agency operative on weapons of mass destruction."

At issue is whether Mr. Novak's government sources blew her cover as a CIA agent, in violation of the Intelligence Identities Protection Act of 1982.

That law aims to protect the identities of "certain United States undercover intelligence officers, agents, informants, and sources." Mr. Wilson has claimed that White House officials leaked his wife's CIA role to the press as revenge for his criticism of the president's case against Iraq. Other observers say the sources were merely steering journalists away from Wilson's allegations.

Q. Why have two senior White House officials - Bush's top adviser, Karl Rove, and Vice Presidential Chief of Staff I. Lewis "Scooter" Libby - faced such intense scrutiny?

In grand jury testimony, several journalists revealed that one or both men had spoken to them about Wilson's wife and her employment.

Toward the end of the investigation, it has become clear that Mr. Fitzgerald has focused more on possible charges of obstruction of justice, perjury, and making false statements, rather than on laws prohibiting public revelation of a CIA official's undercover status. Mr. Rove testified four times and Mr. Libby twice.

Q. How wide was the investigation?

As special counsel, Fitzgerald was tasked with investigating the alleged unauthorized disclosure of a CIA employee's identity. The Department of Justice later clarified that he had authority to investigate any crimes committed in the course of the inquiry, such as perjury, obstruction of justice, destruction of evidence, and intimidation of witnesses.

In all, some three dozen people either appeared before the grand jury or were interviewed by the FBI or Fitzgerald. The special counsel interviewed both Bush and Vice President Dick Cheney last year, but not under oath.

Key individuals who testified late in the process include two aides to Mr. Cheney: John Hannah, an expert on weapons of mass destruction, and David Wurmser, a Middle East adviser.

Among the press, Matt Cooper of Time magazine, Judith Miller of The New York Times, Glenn Kessler of The Washington Post, and Tim Russert of NBC News all testified. Novak is widely assumed to have cooperated with prosecutors, though he has not commented publicly on the case.

Q. What was Cheney's role?

Libby learned about Wilson's wife from his boss, the vice president, before her identity had been made public, according to notes Libby took during the conversation and which were described to The New York Times by lawyers involved in the case.

It is not illegal for Libby and Cheney to discuss classified information; they both have security clearance. But the Libby-Cheney conversation contradicts reports of Libby's testimony, in which he is said to have stated that he first learned of Wilson's wife, and her employment, from reporters.

2002

February The CIA sends Joseph Wilson to Niger to investigate whether Iraq tried to purchase yellowcake uranium. He concludes it did not.

September The British government asserts that Saddam Hussein had attempted to buy uranium from an African country.

2003

January President Bush mentions the British claim in his State of the Union address.

March Mr. Bush orders the invasion of Iraq.

July Mr. Wilson disputes Bush's claim about the Iraq-Africa uranium connection.

CIA Director George Tenet and other White House officials say Bush's reference to African uranium should not have been included in his State of the Union address.

Columnist Robert Novak names Valerie Plame as a CIA operative.

September The Washington Post reports that at least six journalists had been told of the Plame story before Novak's column appeared.

White House Press Secretary Scott McClellan says that "[i]f anyone in this administration is involved in [the leak], they would no longer be in this administration."

The Justice Department launches a probe of the leak.

December Patrick Fitzgerald is named special counsel in the case.

2004

January A grand jury begins hearing testimony. Dozens of powerful government and media figures testify over the next 22 months. White House aide Karl Rove appears before the grand jury four times.

July The British and US governments publish separate reviews of prewar intelligence estimates. The reports express skepticism about the credibility of some aspects of prewar intelligence assessments, and they note that some of the evidence used to allege an Iraq-Africa uranium connection relied on Italian documents that later proved to be forgeries. However, the British and US reports generally support the reasonableness of Bush's claim at the time that he made it.

2005

June US Supreme Court refuses to hear appeals from Ms. Miller and Time magazine's Matt Cooper to avoid testifying before the grand jury.

July Mr. Cooper testifies before the grand jury, after his source releases him from a confidentiality pledge.

New York Times reporter Judith Miller goes to jail to protect the identity of source(s) who leaked Plame's name to her.

September 29 Miller is released from jail and testifies before the grand jury.

October 28 The grand jury was scheduled to expire Friday.