2008, if Nader wins. (Hey, it could happen)
(I) Ralph Nader/Peter Camejo
vs.
(D) Al Gore/Howard Dean (If we elect Nader, we'll elect Gore/Dean)
vs.
(R) Arlen Specter/Rudy Guliani(If Nader wins, Bush will have gotten 5% or so)
Specter could never win the GOP nomination for President. He is a liberal Senator who will be in his 80s when 2008 roles around.
Well, if Nader won an election, I would think the Republicans would have to nominate someone moderate the next time. I didn't consider Specter's age though...