As a parade of politicians and journalists testify in the perjury trial of Lewis "Scooter" Libby, the former chief of staff to Vice President Dick Cheney, courtroom illustrators and editorial cartoonists would do well to draw each witness, the prosecution and the defense in clown costumes and top hats.

This entire spectacle, after all, is a nothing but a three-ring circus sideshow.

The genesis of the case goes back to the summer of 2003, near the start of the Iraq war, when former U.S. Ambassador Joseph Wilson publicly criticized the Bush administration's reasons for invading the country. Eight days later, columnist Robert Novak revealed that Mr. Wilson's wife, Valerie Plame, was a CIA officer.

A federal investigation was launched to determine who leaked Ms. Plame's identity. Within months, Special Counsel Patrick Fitzgerald had determined that former Deputy Secretary of State Richard Armitage inadvertently told Mr. Novak that Ms. Plame worked for the CIA.

Then a funny thing happened. Rather than end his expensive investigation, Mr. Fitzgerald ramped it up. He couldn't simply walk away from the probe and tell his masters, "Nothing to see here, folks." He was expected to land a big fish. To do that, he had but one alternative: catch someone lying.

By summer 2004, reporters were being threatened with jail time if they failed to name their confidential sources in the Bush administration. Liberal pundits and opportunistic Democrats began hyperventilating at the prospect that Vice President Cheney might be indicted or forced to resign.

Mr. Fitzgerald saw to it that New York Times reporter Judith Miller, who refused to reveal her sources to a grand jury, was sent to jail for 85 days. He did this even though he knew the identity of Mr. Novak's source and that Ms. Miller, at best, was a peripheral figure in the case.

In the end, Mr. Fitzgerald's original charge yielded no indictments. But federal prosecutors nabbed their sucker. They allege that Mr. Libby lied during the investigation.

Ultimately, this trial isn't about Mr. Libby or Ms. Plame, but about leakers in general. It's about punishing those who defy the will of the mighty. It's about denying journalists the ability to protect sources who come forward to expose government wrongdoing. It's about frightening potential whistleblowers into keeping quiet.

"There's certainly going to be a hesitation among sources as they see this trial unfold and watch what happens with Libby," Charles Tobin, a media law attorney with the firm of Holland & Knight, told The Washington Post. "Will they have conversations with reporters if they think those conversations can be used to prosecute them?"

Maybe not. And that's a wonderful comfort for those in power at any level of government.

Nevada journalists enjoy the protection of one of the strongest shield laws in the country. Reporters here cannot be compelled to reveal their sources to overzealous authorities, but that safeguard does not extend to federal proceedings.

Had a federal shield law been in place more than two years ago, Ms. Miller and every other journalist paraded before Mr. Fitzgerald's grand jury -- and their sources -- would have no reason to fear the results of the current judicial spectacle in Washington.

It's richly ironic that most of the left-leaning mainstream media initially applauded Mr. Fitzgerald's inquiry on the chance that it might damage the Bush administration. Now they're hoping the trial doesn't inflict too much damage on the press itself.

It's time for Congress to pass a federal shield law, not only to prevent such mockeries of justice, but to ensure the taxpaying public can remain aware of the worst their governments have to offer.