It ought to be obvious that you can only change a major party by participating in it and joining its internal struggles, and that you can't influence a political organization by walking away from it.
Does Michael Medved actually practice the platitudes he preaches? Do any of the rest of the crowd of 'can't wait to bash the libertarians' around here? Are all of you members of PETA, GreenPeace, Democratic Underground, StormFront, the U.N. --- active members, valiantly struggling to change them from within?
If not, you're either hypocrites, or you need to stop using this tired canard with zero validity.