The tendency of the media to be enamored with John McCain. Being "on the tire swing" is often used on blogs as a shorthand for being in the tank for McCain. It originated from a reader of Talking Points Memo and refers to an overly chummy gathering of media people at McCain's ranch. See: http://talkingpointsmemo.com/archives/209567.php
I wouldn't expect much from the interview McCain interview with XYZ, he's on the tire swing.