A US journalist has been sent to prison for refusing to reveal her sources in an investigation into the unmasking of a covert CIA agent.
Miller (left) says she has a duty to protect her sources
Meanwhile, another reporter under threat of jail has agreed to testify in the same inquiry.
The case is one of the most serious legal clashes between the media and US government for decades. BBC News answers the key questions.
How did it start?
The case against journalists Judith Miller and Matthew Cooper stems from an inquiry that set out to identify sources that outed CIA officer Valerie Plame.
Ms Plame is married to former ambassador Joseph Wilson, who in July 2003 went public about his role in investigating reports that Iraq had tried to buy uranium in Niger.
Mr Wilson criticised the Bush administration, saying it had "twisted" evidence to exaggerate the Iraqi threat in the run-up to war.
It is alleged that senior administration officials then leaked details of Ms Plame's role as a CIA employee to six Washington journalists in a bid to undermine Mr Wilson.
Columnist Robert Novak - whose report sparked the row - wrote that an official had told him the trip was inspired by Ms Plame.
What happened next?
The story blew up into a major political storm once it emerged that the CIA had asked the Justice Department to open an inquiry into the leak.
There was - and is - rampant speculation on who might have leaked the name.
The White House has denied that it was Karl Rove, the president's closest domestic political advisor, but there is still speculation linking Mr Rove to the affair.
The furore also concentrated attention on the weaknesses in President Bush's case for going to war with Iraq, leaving the Democrats smelling blood.
Meanwhile, the Justice Department turned its preliminary investigation into a full-scale criminal probe headed by special counsel Patrick Fitzgerald.
Why did the two reporters get caught up in the scandal?
After the Novak column in July 2003, Time magazine journalist Matthew Cooper wrote a piece for Time's website saying that "some government officials" had provided him with information similar to Novak's.
Miller, meanwhile, spoke one or more sources about the story, but never actually published anything.
The reporters subsequently refused to co-operate with the leak investigation, claiming they should not have to reveal their sources because of press freedoms guaranteed in the US Constitution.
That defence was over-ruled by a court in Washington, and the US Supreme Court last week declined to intervene.
But Time magazine last week agreed to comply with a federal subpoena and surrender Cooper's notes and files on the story.
What crime has been committed?
Miller and Cooper were sentenced to 18 months in jail for contempt of court for refusing to reveal their sources to the grand jury investigating the leak. They were allowed to remain free until their appeal.
On Wednesday, Cooper told US District Judge Thomas Hogan that he was prepared to testify after being freed from his obligation to secrecy by a personal intervention from his source.
But Miller is still refusing to comply and has been jailed. She is likely to serve only four months, however - as the mandate of the grand jury expires in October.
With respect to the wider leak inquiry, it is a crime for an official to reveal the name of a CIA undercover operative to someone without security clearance and the CIA always follows up such leaks. The penalty upon conviction is up to 10 years in prison.
However, some commentators have questioned both whether Ms Plame was working covertly at the time she was unmasked, and whether the administration's alleged complicity in publication of the name still means a crime has been committed.
What implications does this have for the media?
Media advocates have said the use of anonymous sources could be curtailed if the pair are forced to testify, even though Miller never wrote about the story.
They argue that anonymous tip-offs have been vital to exposing previous government scandals, including Watergate and the furore over the Pentagon Papers, the secret record of the Vietnam War.
In court documents cited by several US media outlets, Fitzgerald on Tuesday came down hard.
"Journalists are not entitled to promise confidentiality - no-one in America is," he wrote.
Last week in court he argued that even former US president Richard Nixon was forced to bow to the will of the courts, obeying an order to hand over tapes during the Watergate scandal.
What has happened to Novak?
Novak, whose column cited as sources two unidentified senior administration officials, has refused to say whether he has testified before the grand jury or been subpoenaed.
He has said he "will reveal all" after the matter is resolved and that it is wrong for the government to jail journalists.