Let there be one clear lesson from the Valerie Plame investigation: Thou shalt not lie to prosecutor Patrick Fitzgerald.

In a court filing Friday, Fitzgerald told U.S. District Court that I. Lewis "Scooter" Libby should be sentenced to a term of between 30 to 37 months, or between two and a half and a little more than three years. Considering that President Bush still has the power to pardon Libby at any point in the next 21 months, there is a good chance that Libby will not serve a full term.

The most notable part of Friday's 18-page filing is Fitzgerald's full-throated defense of his own decision to prosecute Vice President Dick Cheney's chief of staff, despite the hue and cry of Libby's political supporters, some of whom apparently spoke on Libby's behalf during the pre-sentencing process, though the identities of those supporters and what they said has been redacted from the filing.

"While the disappointment of Mr. Libby's friends and supporters is understandable," Fitzgerald writes, "it is inappropriate to deride the judicial process as 'politics at its worst' on behalf of a defendant who, the evidence has established beyond a reasonable doubt, showed contempt for the judicial process when he obstructed justice by repeatedly lying under oath about material matters in a serious criminal investigation."

Fitzgerald continues: "Mr. Libby's prosecution was based not upon politics but upon his own conduct, as well as upon a principle fundamental to preserving our judicial system's independence from politics: that any witness, whatever his political affiliation, whatever his views on any policy or national issue, whether he works in the White House or drives a truck to earn a living, must tell the truth when he raises his hand and takes an oath in a judicial proceeding, or gives a statement to federal law enforcement officers."