BOB GARFIELD: When New York Times reporter Judith Miller was put behind bars Wednesday, it was easy to get caught up in these swirling ironies of the case. For starters, she was jailed for failing to identify the source for a story she never wrote. It was columnist Bob Novak who wrote "Outing CIA Officer Valerie Plame" with information illegally leaked by at least Bush Administration officials. Then there's the fact that Novak who, unlike Miller, presumably did testify before the grand jury, diming out his sources, or copping the Fifth, is in no legal trouble whatsoever. Then there's the political irony. The New York Times, supposed citadel of the great liberal media conspiracy, sacrificing one of its own to protect the perpetrators of Republican dirty tricks. And finally, there's the bizarre comeuppance. Miller, after all, is the reporter who carried the Administration's water leading up to war by writing ominous weapons of mass destruction stories based on dubious anonymous sources, chiefly White House pet and noted swindler, Ahmed Chalabi who was making it all up. This isn't a first amendment showdown, it's an O'Henry story with sound bytes.

BOB NOVAK: Well, I deplore the thought of reporters--I've been a reporter all my life--going to jail for any period of time for not revealing sources. And there needs to be a federal shield law preventing, as there are shield laws in 49 out of 50 states. But my lawyer said I cannot answer any specific questions about this case until it is resolved, which I hope is very soon.

BOB GARFIELD: That was Novak on CNN's Inside Politics last week, suggesting that Congress need only legislate a reporter's source privileged to make these confrontations go away. But most state shield laws don't confer absolute privilege in criminal investigations. And with the blogosphere making the definition of "journalist" murkier by the day, even the most far-reaching of such laws will likely become less and less practical to maintain. Moments before being led away to jail, Miller herself acknowledged that the court had acted correctly. She declined to name her source not because she thought it was the lawful thing to do, but because it was what she promised to do. Her boss, Times Executive Editor Bill Keller, made the same point on Wednesday.

BILL KELLER: At this point the law and principle have come into a collision. Judy has--you know, the law presented Judy with a choice. She could betray her source and go free, or she could go to jail.

BOB GARFIELD: And therein, at least, the nub of the affair, not whether anonymous sources are important in revealing the inner workings of government, especially one as secretive as the Bush Administration--of course they are--and not whether reporters need to protect their sources. Of course, they do. The moral of this story is that not every anonymous source is himself or herself a principled participant. Some of them are simply Machiavellian scoundrels, and we should take care about whom we make professional commitments to, and equal care about what commitments we are making. The solution is simple contingency, a promise of confidentiality with strings attached, each string specified in advance.

WOMAN: You have the right to remain silent. Anything you say can and will be used against you in a court of law.

BOB GARFIELD: Well, why not a journalistic Miranda warning, one that says this agreement is null and void if you, Mr. Source, are a liar or a fraud or engaged in criminal behavior unknown to this reporter right now because then, pal, all bets are off. Would that have a chilling effect on the flow of information inside the beltway? Probably. It would also have a chilling effect on the naked manipulation of the press. Judy Miller, considering her Pulitzer-prize winning way of conducting journalistic business, might be especially chilled. But she also wouldn't be in the cooler right now. (MUSIC)

BROOKE GLADSTONE: Coming up, an encyclopedia that records history as it happens and why the book has never closed on an 80-year-old legal case.

BOB GARFIELD: This is On the Media from NPR.