My parents for example and my husband’s mother would vote Democrat no matter who was the candidate, Obama or Piggly Wiggly.
So would my sister and her husband and her husband’s family. Sigh...
My mother and sister are the same. In terms of politics at the dinner table, I often feel like a psychiatrist talking to his patients, or perhaps a Priest talking to a possessed person.
Trust me, I understand your problem all too well.