If you wanted a textbook example of what is wrong about appointing a special prosecutor, the prosecution of White House aide Lewis "Scooter" Libby is a classic. Let's go back to square one to see how this sorry chapter in criminal law unfolded.

The charge that was trumpeted through the media was that the Bush administration had leaked the fact that Joe Wilson's wife worked for the C.I.A. in retaliation against him for saying that Saddam Hussein was not seeking uranium in Niger, contrary to intelligence reports cited as one of the reasons for invading Iraq.

Since there is a law against revealing the identity of a C.I.A. agent, a great hue and cry went up for a special prosecutor to find and prosecute whoever leaked that information.

Some in the media gleefully anticipated seeing White House adviser Karl Rove, or perhaps even Vice President Dick Cheney, being frog-marched out of the White House in handcuffs.

Attorney General John Ashcroft appointed a special prosecutor, Patrick Fitzgerald, to investigate these charges.

Here is where the story takes a strange and disturbing twist. Today we know what we did not know when it happened -- namely, that Fitzgerald discovered early on that the leaker was not any of the White House officials on whom suspicion was focussed.

It was Richard Armitage in the State Department. Moreover, Joe Wilson's wife had a desk job at the C.I.A. and revealing that fact was not a violation of the criminal law.

In other words, there was no crime to prosecute and there was no mystery to solve as to who had leaked Wilson's wife's name to columnist Robert Novak.

At this point, a regular prosecutor would have decided that he had other things to do than to pursue an investigation of a non-mystery about a non-crime. But special prosecutors are different.

Patrick Fitzgerald insisted on keeping the investigation going for three years -- and keeping secret the fact that there was no crime involved and no mystery about who leaked.

In the course of this pointless investigation, it turned out that some of Scooter Libby's statements conflicted with the statements of some reporters. So Libby was prosecuted for perjury and obstruction of justice -- and a Washington jury convicted him.

Not only did Libby's recollections differ from that of some reporters, some of those reporters differed among themselves as to what had been said and some differed in their later testimony from what they had said in their earlier testimony.

The information about Joe Wilson's wife was so incidental and trivial at the time that it is hardly surprising that it was not fixed in people's minds as something memorable. Only later hype in the media made it look big.

With Libby handling heavy duties in the White House, there is no reason for his memory to be expected to be better than that of others about something like this -- much less to convict him of perjury.

As for the pay-back conspiracy theory of a Bush administration-inspired leak because of Wilson's opposition to the Iraq war, Richard Armitage was not an Iraq war hawk and columnist Robert Novak opposed the war. They had no reason to discredit Wilson.

Even the term "leak" is misleading. In the course of a discussion, Novak simply asked Armitage why someone with no expertise like Joe Wilson had been sent to Niger in the first place -- and Armitage's answer was that he was sent at the suggestion of his wife, who worked at the C.I.A.

Novak's column was not about that fact but mentioned it in passing. From this the liberal media went ballistic with conspiracy theories that we now know were totally false.

A man's life has been ruined because his memories differed from that of others -- whose memories also differed among themselves -- and media liberals are exulting as if their conspiracy theories had been vindicated.

More important, how are we to expect highly qualified people, with far better options than a government job, to risk being put through the Washington meatgrinder because of politics, media hype and special prosecutors who can create crimes in the course of an investigation, when there was none to begin with?