Before he enter on the execution of his office, he shall take the following oath or affirmation:--"I do solemnly swear (or affirm) that I will faithfully execute the office of President of the United States, and will to the best of my ability, preserve, protect and defend the Constitution of the United States."

Article II, Section I of the U.S. Constitution

WASHINGTON, July 2 — President Bush said today that he had used his power of clemency to commute the 30-month sentence for I. Lewis Libby Jr., the former top aide to Vice President Dick Cheney, who was convicted of perjury in March and was due to begin serving his time within weeks.

The action, announced just hours after a federal appeals court denied Mr. Libby’s request to allow him to remain free while his case is on appeal, spares Mr. Libby his prison term, but it does not excuse him from stiff fines or probation.

In a statement issued early this evening announcing his decision, Mr. Bush said he had listened to both critics and defenders of Mr. Libby, who was convicted of four felony counts for lying during a C.I.A. leak investigation.