The mercifully ended investigation of former HUD secretary Henry Cisneros is a demonstration of the problem with the now-lapsed independent counsel legislation.

The revelation that FBI agents lied about the use of incendiary tear gas cartridges in the 1993 siege of the Branch Davidian stronghold in Waco shows why something is needed to replace it.

The four-year, $9 million probe of Cisneros, so far as I can tell, amounted to this: He lied to the FBI during a background check for his Cabinet post -- not about an illicit affair or making payments to the woman with whom he had the affair. The lie was about how much he paid her. He told agents he gave the woman, Linda Jones, about $2,500 a month after the affair ended -- apparently the same story he gave his wife, with whom he later reconciled. In fact, according to prosecutors, he gave Jones more than $250,000 from 1990 to 1994.

For me, the most interesting question is where the mayor of San Antonio, a career-long public servant, managed to get that kind of money. I don't mean to say that lying to the FBI is okay, but it does seem to me that not all lies are necessarily equal.

This particular lie, to which he owned up on Tuesday, just before he was scheduled to go on trial, led to a settlement in which Cisneros agreed to pay a $10,000 fine and a $25 court assessment. No jail time, no probation, no legal impediment to the resumption of his political career.

How can the same independent counsel who thought it worth four years and $9 million of government money to nail Cisneros also think this chump-change settlement makes sense?

The settlement probably makes more sense than the chase. It just wasn't that big a deal, and it's hard to believe an ordinary criminal prosecutor would have put that much time and money into it.

And that's the problem with special prosecutors. Independent Counsel David M. Barrett was, as far as I can tell, no monomaniacal Kenneth Starr on some holy crusade. He was just a guy trying to do his job. But when the job entails unlimited time and unlimited funds in the pursuit of a single suspect -- and when your entire reputation rests on the results of that single case -- it's hard to keep a sense of proportion. The surprise is that more special prosecutors didn't lose their way.

But Waco is a reminder that there are times when public confidence demands outside investigation. If the FBI lied about the use of incendiary devices at the Branch Davidian compound -- even if the devices did not trigger the fire in which scores of men, women and children died -- you don't want the FBI to lead the investigation of those lies six years later, after the truth leaks out. It would be like having the CIA investigate whether its agents helped bring crack cocaine into inner-city America, as a West Coast journalist charged three years ago. The journalist may have been wrong and the CIA innocent, but wouldn't you want assurances from someone other than the accused agency?

Attorney General Janet Reno, in the interest of public confidence and her own reputation, needs to have an outsider look at what did or didn't happen in Waco. Did the FBI knowingly lie, and was the agency's director in on the lies? Were its lies consequential? Is it telling the truth now -- or only enough truth to quell the present embarrassment? Were lawmen lying to Reno when they told her that small children were being abused inside the compound? Were the lies the result of frustration over the 51-day siege or the result of some misbegotten vendetta against David Koresh, leader of the Branch Davidians?

Reno needs the answers as badly as the rest of us do. She knows it, too, which is why she approached former senator John C. Danforth of Missouri as a candidate for the job. Danforth, a Republican widely respected across party lines and also a former state attorney general, has the kind of credibility that could give most Americans a fair measure of confidence in his findings, whatever they are.

But given our unsettling experience with special prosecutors, it might be a good thing if the independent role is limited to investigation, not prosecution.

What we need is someone with an interest in developing relevant and reliable information, not in nailing culprits.