Blowback is what happens when the consequence of actions you have taken come full circle and slap you in the face. That happened to us in Afghanistan, after we supported the Mujahideen against the Soviets and then Muslim fighters installed the Taliban. Now we may be seeing blowback against the press.

Last month, The New York Times and The Washington Post won Pulitzer Prizes for their stories on National Security Agency surveillance and CIA secret prisons in Eastern Europe. Soon, they may be getting subpoenas. If so, the papers shouldn't be surprised.

In July 2003, when columnist Robert Novak printed the name of a CIA analyst, the Times self-righteously demanded an investigation of White House aides to determine if they violated the law by leaking her name. With glee, Bush haters charged that this disclosure wreaked grave damage on national security. In time, a special prosecutor was appointed. He has charged no one with violating the law at issue, the Intelligence Identities Protection Act. But he did jail then-Times reporter Judith Miller for refusing to testify, until she finally agreed to do so. Blowback.

This may be only the beginning. Two weeks ago, the CIA fired analyst Mary McCarthy for disclosing classified information to a reporter. She was widely reported to be a source for the Post story on secret prisons, but her lawyer denies it. The leak is being investigated by the Justice Department. A prosecution, of leaker or leakee, could follow.

And so could a prosecution for the Times' NSA story. That will seem outrageous to many, as there have been precious few prosecutions of leakers of classified information in our history and none of journalists. And don't journalists have a right to protect their sources?

The answer to the last question is yes, in some states, but no in federal law, as the Supreme Court ruled in 1972 and as the trial and appeals courts ruled in the Judith Miller case. And the Espionage Act of 1917, as amended in 1950, very clearly makes it a criminal offense to transmit or receive classified information.

"If these statutes mean what they seem to say and are constitutional, public speech in this country since World War II has been rife with criminality," wrote law professors Harold Edgar and Benno Schmidt. "The source who leaks defense information to the press commits an offense; the reporter who holds on to defense material commits an offense."

Why haven't there been more Espionage Act prosecutions? One reason is that the government often fears a trial will reveal secret information. Another is that there is a widespread consensus that there is rampant overclassification -- the government sometimes classifies newspaper articles, but it isn't going to prosecute anyone for leaking them.

But the NSA surveillance and the secret prisons were things the government definitely wanted kept secret, and it has argued plausibly that their publication has damaged the interests of the United States. Bill Keller and Leonard Downie, the highly respected top editors of the Times and the Post, have said that they decided publication wouldn't hurt national security. But the law, perhaps unwisely, doesn't give them the final decision on that.

There have been only a few leak prosecutions under the Espionage Act. A retired CIA analyst was convicted for leaking documents to Jane's Fighting Ships in 1984. Defense Department employee Lawrence Franklin was sentenced in January to 12-and-a-half years in prison for disclosing classified information to two employees of the American Israel Public Affairs Committee. A prosecution is underway of the two recipients of the leak, who stand in the same legal shoes as the Times and Post reporters.

In effect, there has been an informal truce between prosecutors and the press -- Justice Department guidelines discourage asking reporters about sources. But in the Novak leak case, the press's demands for an investigation led to just such questioning.

So now the government can make a case for prosecution by quoting the Times' editorials on the Novak leak case. It's certainly plausible that there was much less damage to national security in that case than in the NSA and secret prison stories. There's an argument here for government forbearance: Prosecutions will dry up a lot of sources. But there's also an argument for forbearance by the papers. An argument about blowback.