If Huckabee left the GOP, would Hagee, Tony Perkins, and all the other evangelicals leave too? Huckabee is an gifted orator, and if he did create a third party, it could gain traction, but we'll see if he can win the GOP presidential nomination if he runs in 2016.
Spoiler: he cannot.
Neither can a candidate who supports marriage equality. Because of Huckabee. (And people like him.)
My only point was, yes, the Huck crowd drags the nominee to the right on social issues, but they never actually stand a chance of winning. The GOP will elect a respectable candidate (by non-biased standards) like Bush or Christie or Walker or Paul in 2016. Sure, Democrats will paint whomever the nominee is as a crazy extremist come general election time, but the ACTUALLY fringe candidates (Cruz, Santorum, Huckabee, etc.) never get the nomination.