In my case, I say nothing to my liberal sister. If I don't get her angry, she probably won't vote this time. If I tick her off, she will go to the polls just to spite me.
you said: If I don't get her angry, she probably won't vote this time
You're lucky. I wish it was that easy to keep my liberal sister and brother-in-law from voting!
It seems to me that this election is running largely on emotion on both sides, and an intelligent conversation with someone who is rabidly sticking to their position is useless.
Based on my own experience, whether it's talking about politics or not, just as someone is likely not going to convert me to their side, I'm not likely to convert them to mine.