The trial of a former White House aide is under way in Washington which is likely to reveal how the Bush team acted in the run-up to the Iraq war.
Lewis Libby was in the White House inner circle
Lewis "Scooter" Libby is charged with lying about the disclosure of a CIA agent's identity in 2003.
It has been alleged Valerie Plame was "outed" in revenge for her husband's attack on President George Bush's use of intelligence to justify the war.
The case is not about the leak itself but the alleged cover-up.
Deliberately revealing an agent's name is a serious offence in the US and the leak sparked a high-level criminal inquiry.
A grand jury looked into claims that leading White House officials set out to discredit former US ambassador Joseph Wilson, revealing his wife's identity in the process.
Jurors will have to decide whether Mr Libby, once chief of staff to Vice-President Dick Cheney, lied to investigators examining the disclosure of Ms Plame's name.
At the trial's opening in Washington, prosecutor Patrick Fitzgerald described a tumultuous week in 2003 when he said the White House was under "direct attack" from Joseph Wilson.
Mr Wilson had accused the Bush administration of insisting Iraq was trying to buy uranium for weapons long after it knew this to be untrue.
Mr Wilson argues that his wife was betrayed
His wife's name and job appeared in a newspaper column shortly afterwards, thus ruining her career.
The prosecution said Mr Libby learned from five people - including Dick Cheney - that Mr Wilson's wife worked for the CIA, and that he had at least nine conversations about the fact before he claimed to have learned about Ms Plame's identity on 10 July 2003.
"But when the FBI and grand jury asked about what the defendant did," Mr Fitzgerald said, "he made up a story."
Mr Libby has said any inaccuracies in his testimony were because he was preoccupied with major national security issues at the time.
Defence lawyer Theodore Wells countered by seeking to cast Mr Libby as a scapegoat, saying he was an innocent man who had been "wrongly and unjustly and unfairly accused".
Mr Wells said that Bush administration officials blamed Mr Libby for the leak to protect President Bush's top political adviser Karl Rove because of his own disclosures.
An investigation by White House officials cleared Mr Rove of any wrongdoing but stopped short of doing so for Mr Libby.
Mr Libby, who was asked to refute Joseph Wilson's criticisms, felt betrayed and went to the vice president with his concerns of becoming "a sacrificial lamb", the defence said.
After hearing Mr Libby's concerns, Mr Cheney wrote a note saying that one staffer should not be sacrificed for another, Mr Wells said.
Lengthy jury selection
The jury selection period took four days, an unusually long time, because so many candidates were critical of the White House team, especially Mr Cheney, who is expected to be a major witness.
Correspondents say as a result of weeding-out bias, the jury is not representative of Washington, where registered Democrats outnumber Republicans by 9-to-1 and blacks outnumber whites by more than 2-to-1.
The jury has 10 whites and two blacks.
Mr Libby, who faces five separate charges, could be imprisoned for up to 30 years - up to 10 years on the obstruction charge and up to five years on each of the others.
However, lawyers say that any sentence would probably be much shorter because, if he is found guilty, the offences might be taken as part of a single action and run concurrently. He also faces a maximum fine of $1.25m (£637,000).
He has said he is confident of being exonerated. The trial is expected to last four to six weeks.