Rick Santorum thought he had Megadeth frontman Dave Mustaine's endorsement in his pocket, but he'll have to work a bit harder on the campaign trail to get it back as the metal guitarist clarified his comments. "Contrary to how some people have interpreted my words, I have not endorsed any presidential candidate," the rocker said in a release obtained by Billboard last night. "I respect the fact that Santorum took time off from his campaign to be with his sick daughter, but I never used the word 'endorse.'" That may set Santorum back in the Atlantic Wire's battle of the band endorsements, but the candidate appears to be doing fine in the polls for now.