Your inference is that voters only vote their party.
That may be true for a large percent of the voting public that will rationalize why they will vote their party and then there are those who put party first, no matter what.

What you are suggesting is that if Trump were a democrat he would have all his current values and beliefs. We know that would not be possible and remain a democratic candidate.

So, while an intellectual exercise at best and bait at worst.......it really is not a viable question given the differing party philosophies on too many issues....especially those that delineate R or D.