Should I maintain a relationship with my mother or cut her out of my life?

My mother and I have always had an up and down relationship. She is a very judgemental cruel person. Her last episode pushed me to the brink. I am 53 have 3 great kids and I am divorced. I have a lot of friends and am usually a funny, kind person. In talking to her the other day, she asked my opinion on a political issue when I paused to answer she ran right over me and voiced her biased, bigoted and toxic views. I finally informed her that she had asked me something and never bothered to let me finish. She got mad, saying I am always making a big deal out of nothing. Then when I started expressing myself ( in a respect soft tone of voice) she responded with "I can't talk to you anymore because we don't agree. I don't talk to people who don't agree with me and most people think like me. I don't like your generation they all have a stupid attitude." I countered with by telling her I was not insulting her point of view, that a good discussion is two people giving ideas back and forth. She said goodbye and I haven't heard from her since. I know from previous incidents similar to this that now I am supposed to apologize, or she won't speak to me again. Frankly, I really don't want her in my life. She has treated my youngest child like garbage because she didn't like her father. She went so far as to tell my daughter that if there was any fairness in the world he would die in surgery during a procedure. Another time she purchased her a Xmas ornament with 'Merry Christmas to a great teacher' on it., while buying my other two an appropriate gift. When I have a speaking relationship with her I feel I am betraying my daughter. Should I cut my losses or put it aside because she is 78 and my mother?? please help with this decision.