Hmmmmmmm.........have you told her that this bothers you? If you cannot communicate openly now, it likely won’t get better.
I think I’d try to, in person, have a heart-to-heart about how important this is to you. If she is apathetic and admittedly uninformed, ask her if she would accept your educating her.
I would lead with the faith that you share since much of politics today is spiritually connected inasmuch as it involves morality, etc.
Help her to understand that individual political decisions are intricately entwined with one’s faith. If her faith is as you say, she may be open to hear you out.
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.