The last time it happened, the officer claimed he was about a quarter of a mile from where he was whenever I passed him and in court he even changed the direction he was heading - from due South to due East.

I filed a complaint against him and the allegation was "investigated" and the finding was "insufficient evidence" to bring charges.

FITZGERALD: I'll be blunt.

That talking point won't fly. If you're doing a national security investigation, if you're trying to find out who compromised the identity of a CIA officer and you go before a grand jury and if the charges are proven -- because remember there's a presumption of innocence -- but if it is proven that the chief of staff to the vice president went before a federal grand jury and lied under oath repeatedly and fabricated a story about how he learned this information, how he passed it on, and we prove obstruction of justice, perjury and false statements to the FBI, that is a very, very serious matter.

FITZGERALD: And I'd say this: I think people might not understand this. We, as prosecutors and FBI agents, have to deal with false statements, obstruction of justice and perjury all the time. The Department of Justice charges those statutes all the time.

When I was in New York working as a prosecutor, we brought those cases because we realized that the truth is the engine of our judicial system. And if you compromise the truth, the whole process is lost.

In Philadelphia, where Jack works, they prosecute false statements and obstruction of justice.

When I got to Chicago, I knew the people before me had prosecuted false statements, obstruction and perjury cases.

FITZGERALD: And we do it all the time. And if a truck driver pays a bribe or someone else does something where they go into a grand jury afterward and lie about it, they get indicted all the time.

Any notion that anyone might have that there's a different standard for a high official, that this is somehow singling out obstruction of justice and perjury, is upside down.

If these facts are true, if we were to walk away from this and not charge obstruction of justice and perjury, we might as well just hand in our jobs. Because our jobs, the criminal justice system, is to make sure people tell us the truth. And when it's a high-level official and a very sensitive investigation, it is a very, very serious matter that no one should take lightly.

  Resources are limited. Judgments as to which cases to pursue must be made. Ability to prove cases is a predominant factor but it is no the only one.

   One factor which should be considered is the harm caused by the alleged crime. As an example, a crooked accountant lying about the books of a small businessman client suspected of tax evasion and hiding/destroying papers relevant to the investigation  does not cause the same degree of harm as when a very high ranking federal official lies about an investigation related to his official duties. The same statutes might apply to the accountant as to Libby, but which case is more important?

   The argument that special counsels are relieved of the resource limitation issues facing "regular prosecutors" and more likely to prosecute "ancillary" crimes is probably true, but that is because they are appointed only in "special" cases.