You can do what I have done: end interaction beyond brief ersatz pleasantries during holidays/weddings/funerals. When someone is willing to subject you to involuntary servitude, taxation without representation, violation of equal protection (or what have you), they ought not expect business as usual. Blood may be thicker than water, but it is not thicker than freedom.
Mr. niteowl77
I'm the sole conservative in a very large family of solid liberals. I learned that "blood isn't thicker than freedom" during the 2008 election.
I've exchanged little except the most basic holiday greetings and such with family since then, and it doesn't appear that I'll be doing anything other than that from here on out.