I think really she doesn’t quite understand, as you say, that “individual political decisions are intricately entwined with one’s faith.” She seems to think politics is just Candidate A or Candidate B and that it’s about impersonal issues she’d rather not bother with. I’m the opposite which is why a simple vote gets me worked up. But I suppose I should realize that that took a while for me to understand (thanks almost fully to FR), and that it may take a while with her. I should probably approach any discussions from a conceptual, personal and faithful point of view.
Probably a good plan. Above all, be open and be who you really are. If she loves you, she will appreciate that even if you don't see eye to eye.