OCCUPATION: U.S. Senator, former presidential candidate
PREVIOUS APPEARANCES ON THE TIME 100: 2
PRO: Rather than slink away after his failed presidential bid, McCain has remained a firecracker in the Senate, counseling the President on issues like Iraq and sparring with him on the stimulus.
CON: Fairly or not, his campaign with its rickety debates, combustible staffers and mercurial messages is seen as the tipping point for the current Republican malaise.