The news media’s ability to use leaks to keep the White House honest is threatened as never before by the unanticipated consequences of the investigation into the White House’s own leaks of classified information to discredit a critic.

Some government officials are itching to exploit that investigation as a precedent for using the threat of long jail terms and massive fines to force reporters to finger their confidential sources. The precedent was set, ironically, by the special counsel investigating leaks by White House officials, including (we now know) Karl Rove and I. Lewis (Scooter) Libby.

Few leakers and no reporters in American history have been prosecuted for disclosing classified information. But that may change.

Under the Justice Department’s interpretation of a 1917 espionage law, both those who leak government secrets and those who publish them are felons. It may be no defense to argue that the leaks did little damage to national security, or that they exposed official misconduct or deception.

Subpoenas of journalists have not been so common in more than 30 years. Former Pentagon official Lawrence Franklin was sentenced to 12 years in prison last month for orally sharing classified information to help two then-staffers of a pro-Israel group lobby for a harder line on Iran. Those two men face trial in April for receiving classified information and sharing it with reporters and Israeli officials. They are the first private citizens ever prosecuted for such activities. Reporters could be next. Meanwhile, Senate Intelligence Committee Chairman Pat Roberts said on February 17 that he may push for new legislation making it easier to prosecute leakers.

Unless wise heads in the Justice Department, the judiciary, Congress, and the media themselves steer a steady course through this gathering storm, the executive branch will acquire more power than ever to hide its actions from public and congressional scrutiny.

This prospect may not trouble you if you think that President Bush and his successors should have remained free to continue his secret warrantless surveillance program forever, with no real congressional or judicial oversight and in disregard of the Foreign Intelligence Surveillance Act.

And it may not trouble you if you think that we should never have known about the classified August 2002 Justice Department memo claiming that the president has virtually unlimited power to order the torture of suspected "enemy combatants" in disregard of federal criminal law. Or if you wish that the Watergate cover-up had succeeded.

But for those who see undue secrecy as an incubator of deception and abuse, there is cause for alarm.

A troublesome chain of events began in the summer of 2003, with the White House leaks of the identity of undercover CIA agent Valerie Plame in the wake of her husband’s highly publicized attacks on Bush’s claim that Saddam Hussein had sought uranium in Africa. The media clamored for an aggressive investigation by a special prosecutor. To their misfortune, they got one: U.S. Attorney Patrick Fitzgerald, of Chicago.

For decades, federal prosecutors had shied away from subpoenaing reporters. Even after the Supreme Court’s 1972 ruling that reporters can be jailed for refusing to disclose their sources, prosecutors assumed that subpoenas would bring them only hostile publicity because reporters would choose jail over betrayal.

But by the time of Fitzgerald’s appointment, trust in the media had fallen so far that hostile publicity had lost some of its sting. Then the dogged Fitzgerald showed that the threat of significant jail time can force some big-time reporters to reveal their sources. He also showed that mounting fines and fallout from contempt-of-court citations could force a powerful media company (such as Time magazine) to turn over e-mail records outing a reporter’s source.

Prosecutors everywhere took note.

So did administration officials eager to build on Fitzgerald’s successes in order to punish leakers and the media alike.

"I’ve called in the FBI, the Department of Justice," CIA Director Porter Goss told the Senate Intelligence Committee on February 2. "It is my aim, and it is my hope, that we will witness a grand jury investigation with reporters present, being asked to reveal who is leaking [classified] information." Bush himself said in December that it had been "shameful" for The New York Times to expose his warrantless surveillance program.

There is nothing new about officials complaining that classified leaks harm national security. Sometimes they have been right. But much of the time they have been wrong.

"It quickly becomes apparent to any person who has considerable experience with classified material that there is massive overclassification and that the principal concern of the classifiers is not with national security, but rather with governmental embarrassment of one sort or another," as Erwin Griswold put it in a 1989 op-ed.

Griswold was the solicitor general who had, unsuccessfully, urged the Supreme Court in 1971 to halt further publication of the Pentagon Papers, a classified Defense Department history of the Vietnam War. He had dutifully recited Nixon administration officials’ claims that publication by The New York Times and The Washington Post would gravely damage national security. But in hindsight, Griswold wrote in 1989, "I have never seen any trace of a threat to the national security from the publication."

Examples of overclassification are legion. They include the government’s reclassification in recent years of a previously published 1948 memo on a CIA plan to drop propaganda leaflets from balloons over Soviet bloc countries, and an October 1950 CIA memo saying that Chinese intervention in the Korean War was "not probable in 1950" — a prediction belied two weeks later by 300,000 Chinese troops.

(These examples were reported in a February 21 New York Times article about a secret, seven-year-old push to reclassify previously public documents.)

Even some leaks that have done great damage have been justified by the public’s need to know. Consider the Abu Ghraib torture photos. Their publication has hurt the United States terribly in world opinion and has helped terrorist recruiting. But when our military tortures ordinary prisoners, the American people should know about it.

In other cases, the cost-benefit calculus is pure guesswork. But our traditions argue against trusting the government to decide — without independent scrutiny — what we should and should not know.

Striking the right balance requires journalistic responsibility as well as prosecutorial restraint. Journalists should not publish every secret they can get their hands on, especially in the face of plausible warnings that publication may do damage.

The editors of The Washington Post and The New York Times were right to give respectful hearings to President Bush’s warnings that articles they ended up publishing would damage national security. They were also right to delay publication and omit some details to minimize the damage. Whether they were right to publish when they did is more difficult for an outsider to assess.

For reasons outlined in my February 11 column, I suspect that little harm was done to national security by The Times’s December 16 disclosure, over Bush’s objection, of his eavesdropping program. And on the benefit side, it was this disclosure that made possible a much-needed debate about the Bush program’s wisdom and legality, and the need for congressional and judicial oversight.

The award-winning November 2 revelation, also over Bush’s objection, by The Post’s Dana Priest that the CIA had been holding and interrogating high-level Qaeda detainees in secret prisons in Eastern Europe seems a closer call.

The major revelation was that some of the CIA prisons — the existence of which had been publicly known for years — were in "a Soviet-era compound in Eastern Europe." The predictable result of publishing it was to expose Eastern European governments to pressure from their own citizens to close down the CIA prisons.

Was this a good thing? Where does The Post want Qaeda leaders held? Does the public’s right to know include the right of people overseas to know things that are of relatively little interest to Americans and may hurt America’s war effort?

I don’t doubt that The Post has plausible answers. And I certainly don’t want to see Priest subpoenaed. I do suggest that the media may fare better in the subpoena wars if they have reasons for publishing government secrets more compelling than "because they are interesting."

Similarly, prosecutors should have reasons for subpoenaing reporters and targeting leakers more compelling than "because it was classified." Judges should rein in subpoena-happy prosecutors. Congress should create a reporter-source privilege if the Supreme Court doesn’t do it first.

And reporters should not make promises to sources that they — and their employers — are not prepared to keep.