Third parties , we have been told, always assure victory for the opposition, an unintended consequence. Third parties have never had enough strength to win in total. The Tea party movement is different and is growing stronger because it is rapidly becoming clear that the established parties, in trying to keep their priviledged positions, are letting stealth marxists, statists, and one worlders destroy the Republic! The only chance America has lies with the true Patriots We the People
Actually, Third Parties have occasionally succeeded. First with Andrew Jackson in 1824, with the death of the Federalist Party, and the birth of the Democrat party. Second with Lincoln, with the birth of the Republican party.
The next Presidential election appears to me to most resemble the Jackson-1824, with Palin in the role of Jackson. This can go one of two ways--Palin stays Republican, and the RINO wing of the party dies (and turns Democrat), or a true conservative party is established, and the Republican party dies.