The Cash Estate (Family) already objected to some lightweight country singer saying that Johnny would have supported McCain.
Thus I can assume that the Cash Catalog is off limits to the McCain Campaign.
However, I do recall that Britney Spears said she supported President Bush. Perhaps Ms. Spears will let McCain use some of her songs.
The songs suck, barely music much less campaign anthems. I don’t know why they use them anyway. McCain would get far greater traction if he only used one — “God Bless America”— written by truly gifted songsmith that understood from his heart what it meant to be an American.