By DOUGLAS JEHL
WASHINGTON, Oct. 25 - Until now, the federal government has rarely proved more impotent than in trying to plug leaks. Most inquiries go nowhere, because the officials and journalists who are the only witnesses to any crime refuse to discuss it.
But in the case of Valerie Wilson, the outed C.I.A. officer, a prosecutor has succeeded in penetrating that sanctum. Unlike any of his predecessors, the special counsel, Patrick J. Fitzgerald, has delved deeply into conversations that government officials and reporters had every reason to believe would remain confidential.
It is not yet clear if Mr. Fitzgerald intends to bring charges that will cast the conversations themselves as criminal, as settings for the exchange of classified information. But even indictments containing less serious accusations against White House officials would bring with them the possibility that reporters would be called as witnesses.
Exchanges between reporters and government officials have always been a central part of how Washington really works. They have served as shortcuts, ways to trade information beyond the glare of television lights and outside of bureaucratic barriers. But Mr. Fitzgerald, who obtained federal subpoenas to compel reporters to testify in the case, is not the only one in Washington who is trying to train a new kind of spotlight on the transactions.
Both the Silberman-Robb commission, in its report this year on intelligence failures related to weapons proliferation, and the House Intelligence Committee, under Representative Peter Hoekstra of Michigan, the Republican chairman, have called for redoubled efforts against leakers.
"The time has come for a comprehensive law that will make it easier for the government to prosecute wrongdoers and increase the penalties, which will hopefully act as a deterrent for people thinking about disclosing information," Mr. Hoekstra said in a speech to the Heritage Foundation in July.
In its report in March, the Silberman-Robb commission described as "understandable but unwarranted" what it called "the long-standing defeatism that has paralyzed action in trying to combat leaks." Notably, the commission suggested that greater pressure on reporters might have been the missing ingredient in past investigations.
"Many people with whom we spoke," the commission said in its report, "said that the best (if not only) way to identify leakers was through the reporters to whom classified information was leaked."
That approach appears to have been the one followed by Mr. Fitzgerald in trying to unravel the mystery of how the identity of Ms. Wilson, an undercover C.I.A. officer, became public in July 2003, initially in a column by Robert D. Novak that identified her by her unmarried name, Valerie Plame. Ms. Wilson is the wife of Joseph Wilson IV, the retired ambassador who emerged in 2003 as a critic of the Bush administration after traveling to Africa in 2002 at the request of the C.I.A. to investigate claims that Iraq was seeking to obtain uranium from Niger.
It is not known whether Mr. Novak provided testimony to Mr. Fitzgerald or to the grand jury in the case. But over an 18-month period in 2004 and 2005, Mr. Fitzgerald has succeeded in obtaining testimony from five reporters about their conversations with senior White House officials, gleaning details about discussions over breakfast, on the telephone and in government offices. The reporters included Tim Russert of NBC News, Glenn Kessler and Walter Pincus of The Washington Post, Matthew Cooper of Time magazine, and, ultimately, Judith Miller of The New York Times, who testified earlier this month after spending 85 days in jail for refusing a court order that compelled her to answer questions from the grand jury.
The reporters' testimony, focusing on discussions with I. Lewis Libby Jr., Vice President Dick Cheney's chief of staff, and Karl Rove, President Bush's top political adviser, appears to have provided Mr. Fitzgerald with a means to corroborate or challenge the accounts provided by the White House officials about the conversations. In the case of Mr. Libby, the journalists' accounts are likely to be central to any case brought by Mr. Fitzgerald, because they have failed to substantiate Mr. Libby's initial assertion that he learned about Ms. Wilson from reporters.
The approach differs from the one pursued by prosecutors in most previous leak investigations, including three prominent cases in recent years, in which inquiries have proceeded without cooperation from journalists involved.
One, a two-year investigation concluded in 2004, found that Senator Richard C. Shelby, Republican of Alabama and former chairman of the Senate Intelligence Committee, was almost certainly a source for news accounts that described classified Arabic-language messages intercepted by the National Security Agency just before the Sept. 11 attacks. Among the messages was one that said, "Tomorrow is zero hour," but the Justice Department decided not to bring charges, instead turning the matter over to the Senate ethics committee.
A second case, against Charles G. Bakaly III, a spokesman for Kenneth W. Starr during his investigation of President Bill Clinton, ended in acquittal in 2000. Mr. Bakaly was accused of being a source for an article in The New York Times that discussed whether President Clinton could be indicted while in office. Mr. Bakaly was charged with lying to investigators in their leak inquiry. At his trial, Mr. Bakaly said he had provided some information to The Times, but said that it had been public and that his responses during that leak investigation had been truthful.
In only one of the three cases, a 2003 episode involving the Drug Enforcement Agency, was anyone convicted of a crime. In that case, Jonathan Randel, a D.E.A. analyst, was sentenced to a year in prison for providing what the agency called sensitive information to The Times of London.
In the past, prosecutors appeared to have operated on the presumption that journalists would not testify in leak cases, and would invoke the First Amendment to try to protect their sources. But those protections apply only in states that provide journalists with specific legal protections to shield their sources, a protection that does not exist under federal law.
In ruling in favor of Mr. Fitzgerald this year, a federal appeals court upheld a lower court ruling that ordered Ms. Miller to testify in the case. The court cited the only previous ruling on the subject by the Supreme Court, a 1972 decision known as Branzburg, which has been interpreted by lower courts as meaning that reporters have almost no protection from grand jury subpoenas seeking their sources.