"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," prosecutors said.