I really don't think Ennis would have voted. Who knows though? It's hard to tell what may have happened to him between the 1980s and now. Assuming he stayed pretty much the same, then I doubt he would have voted. Ennis made it a point to stay disconnected from the world after Jack died. If he did vote though, he definately would have voted Republican. I think Ennis probably would have been both a social conservative and a Republican. Remember one does not need to be a Republican in order to be conservative. However, with Ennis, I think this probably would have been the case.
Edit: Another thought just occured to me:
If Ennis had decided to move to the city for any reason, I think he probably would have taken a job in one of the Unions. If something like that happened, he would have voted Democratic. But he'd definately STILL be a conservative.