Everything of course changes when you get to a general election.
I don't know the exact figures but I think it is about 30% that will only vote for a Republican.
So every Democrat knows about 30% is lost no matter what they say.
It makes no sense to try to appeal to that group at all.
OK, that's not in any way what I was talking about. It's the GOP candidate who will need to appeal to the Trump voters. They hate the mainstream GOP and, given their success so far in the primaries, they will need to be convinced not to stay at home in a huff if Trump isn't the candidate. The only way that can be done is to not totally reject Trump's positions. If they're just given lip service, a greater percentage of those voters will stay home. If they're given more than lip service, a greater percentage of the other GOP voters will stay home because they won't want to be associated with this candidate and a greater number of Democrats will bother to get up off of the couch to vote against him.
Many swing states come down to a few percentage points and there's no way to deal with the Trump bloc without turning off a decent percentage of your potential voters, so that makes a difference.
It's a moot point since the Presidential race isn't going to be close, but any potential GOP strategy for winning means picking up at the margins and having things break their way and they can't do that by turning part of their voter base off.