The Donald is doing everything to validate my decision in 2016 to switch from independent to Democrat.
Why has Donald Trump negatively impacted the idea of being a registered independent in your eyes? LOL.
First off, SC doesn't have party registration.
However, to answer your question, the Republicans choosing Trump as their nominee showed me that they had gone so far away from sanity that as a party they were no longer an option since all supporting the few sane Republicans does at this point is empower the insane ones. That left me a Democrat by default, since for all their faults, the Democrats are still mostly sane.