I’m pretty sure that Sanders supporters will not defect to Trump if Sanders is not the nominee.There are only two Republicans candidates that have enough voter support to be the nominee, and that would be Trump or Cruz. Now I believe that if either one wins the nomination the supporters of the other will support the nominee. I say this because both of them have basically the same ideas.
Where there is a problem is between Hillary and Sanders. They have basically different ideas, are Bernie supporters going to support Hillary?
In an election in which the Republican establishment is saying “Don’t vote for Trump!!!,” I doubt he will be elected.