New York Times (search) reporter insisted Friday that she would not divulge a confidential source to prosecutors investigating the leak of an undercover CIA (search) officer's identify, even if the source permitted her to do so.

Judith Miller (search) faces up to 18 months in jail for refusing to cooperate with prosecutors investigating the leak. Miller, who gathered material for a story but never wrote one, was held in contempt Thursday by a federal judge in Washington.

She said she would have to be certain the source's decision to be identified "is really voluntary" before she considered disclosing the source's name.

"Supposing the investigation is beyond this one source to other sources, whom I may not be able to ask how they feel," Miller said on NBC's "Today" show. "The issue here is whether or not I'm going to protect them and our readers by being able to do my job."

U.S. District Judge Thomas F. Hogan said Miller could remain free while pursuing an appeal.

"We firmly believe we have the law on our side, that the First Amendment protects us from having to give this information," said Times Publisher Arthur Sulzberger, who appeared on "Today" with Miller.

He said journalists need a federal "shield law," such as those in 31 states that protect reporters from testifying about confidential sources.

On Thursday, Hogan called the case "a classic confrontation of conflicting interests," citing Supreme Court rulings that reporters do not have absolute First Amendment protection from testifying before grand juries about confidential sources.

The judge said there was ample evidence that U.S. Attorney Patrick Fitzgerald of Chicago, the special prosecutor in the CIA leak case, had exhausted other means of obtaining key testimony before issuing subpoenas to Miller and several other reporters. There was no evidence prosecutors were engaging in a "fishing expedition" with reporters, Hogan added.

"The special counsel has made a limited, deferential approach to the press in this matter," Hogan said. "Ms. Miller has no right to refuse to answer the questions she now refuses to answer."

Fitzgerald is investigating whether a crime was committed when someone leaked the identity of CIA officer Valerie Plame (search), whose name was published by syndicated columnist Robert Novak on July 14, 2003. Novak cited two "senior administration officials" as his sources.

The Novak column appeared after Plame's husband, former Ambassador Joseph Wilson, was critical in a newspaper opinion piece of President Bush's claim that Iraq sought to obtain uranium in Niger. The CIA had sent Wilson to Niger to investigate that claim, which he concluded was unfounded.

Wilson has said he believes his wife's name was leaked as payback for his outspokenness.

Miller's attorney, Floyd Abrams, said he planned to appeal.