Strangely enough, Bush and Trump both have a ton of cross over appeal (especially Bush), while Rubio (who is by far the most popular among them with Republicans) has almost no crossover appeal at all. Can anyone explain this? Does it all come down to Rubio's extreme hardline views on abortion? Or are there other things that worry Democrats about Rubio as well? For instance his hardline views on Cuba or his flip-flopping on immigration?
I think you're giving voters too much credit in terms of how much they're tuned in to specific issues at this point. I doubt a very large fraction of voters know Rubio's position on Cuba.
One possibility is that it's largely an artifact of name recognition. 35% of voters have no opinion of Rubio, which is a much higher # than you get for Bush and Trump. Without digging into the crosstabs, I'd imagine that, as with many of the lesser known candidates, it's members of their own party who know them better than members of the opposition party. That's going to limit their crossover support in polls like this, if the potential crossover voters don't know anything about the candidate in question.
