South Carolina (of all places) turns out to be the key.
I predict that some “values candidate” will steal Iowa (you know, like President Santorum or President Huckabee). It will be the “end of Trump™”.
Trump will then blow out the doors in NH, “much better than expected™”.
Next comes South Carolina, to answer the question, “can he be stopped™?” South Carolina! So many Christians! So many minorities!
If Trump wins in SC, especially if he wins big, there will be a steamroller effect. If he just squeaks by, or if he loses, there will be a chance for an alternative to appear.
So far only one man has managed to WIN the SC GOP primary and NOT become the GOP nominee.