I see two ways a 3rd party candidate goes forward:
If the Republican nominee is Romney, or similar, it’s guaranteed there will be a Tea Party challenger. I expect Dems in open primary states to go hard for Romney as a 2012 version of Operation Chaos.
If the Republican nominee is a legitimate conservative, a Soros funded MSM backed “independent” will surface.
Those are good predictions. You just know they think it’s a lock—heads they win tails we lose. They figure another RINO will sink us for sure, but that a TEA party-acceptable candidate will be too conservative for the masses. This is going to be a very treacherous election. There is a lot of money and power amassed against us. It’s going to take just the right primary candidate to pull it off. Lets hope it happens.