U.S. District Judge Reggie B. Walton has just denied Scooter Libby’s request to remain free pending appeal of his conviction on charges of perjury, obstructing justice and making false statements. Rejecting Libby’s lawyers’ claims that his appeal raises substantial issues that are likely to lead to a new trial, Walton ordered Libby to begin serving his 30-month prison term pursuant to the usual procedures. Assuming that Libby’s lawyers don’t prevail on an immediate appeal of Walton’s incarceration order, the former chief of staff to Vice President Dick Cheney will be required to report to a federal penitentiary sometime within the next few weeks.

At the White House Wednesday, Tony Snow said he wouldn’t “speculate” as to whether a decision denying Libby’s request to remain free pending appeal would affect the timing of any pardon decision. But there’s a difference between a man facing a prison sentence and a man actually serving one, and that difference will increase the pressure the president faces — from the base he’s losing quickly — to absolve Libby of his sins.