It wouldn't surprise me at all if they do, after all, the Republican party, who generally likes to make a point of claiming they are all inclusive of a broad range of ideas and people, really only want the ones that will tow their pre-ordained agenda (ie, nominate JebBush).
Politico reports:
-
The South Carolina
state party announced on Tuesday that for presidential candidates to
qualify for the South Carolina primary, they must pledge to support the
Republican presidential nominee — and not run as a third-party candidate
— in the general election.
The move comes as two other state parties, North Carolina and Virginia, ponder similar loyalty pledges. It’s an offensive that is implicitly aimed at Trump, who has repeatedly refused to rule out a third-party run.
I think Trump has enough loyalists that would jump the GOP with him. It would likely guarantee a Republican loss in 2016.