In my ever-evolving attempt to improve the quality of my own discourse, I am always seeking to uncover new ways to ensure that debates unfold in good faith. That is to say that there is no good reason to engage a person in conversation if it is clear that a person has no intention of considering what you have to say. Consider what David Henderson has to say about this:
I like arguing. Duh. I write on a blog almost every day. But I don't like arguing with people who are completely closed or who are nasty. Regular readers of my posts have probably figured that out. If someone is nasty to me, the probability that I will bother replying, ceteris paribus, is lower. That takes energy that I don't want to spend.
Similarly with conversations in person. When I figure out that people aren't open or are nasty, I change my approach. For people who aren't open, I switch subjects: ask them about their kids; comment positively on their hair, clothing, whatever; How about those 49ers, etc. For people who are nasty, I leave.The general idea here is that one simply cannot make any headway with someone who refuses to be receptive to your ideas. This might mean that the person in question is close-minded, but it also might mean that the way you have chosen to express yourself does not align well with how they like to communicate. Or, it might mean the the person in question is receptive to many different ideas, but not yours.
The crux of it is that you cannot control the reaction you receive from people. You can do your best to manage your conversational or debate techniques and try in the best imaginable way to state your case in an appealing way, but once the words leave your lips, it simply isn't in your control any longer. It's in the hands of your audience.
In light of this fact, I am going to move forward with debates if an only if I can determine that an attractive outcome is possible. If, for example, someone wants to debate whether Congressional Republicans are "obstructionist," I will only discuss the matter with those who can articulate a more interesting idea than "they should just go along with the Democrats." If someone wants to debate whether ObamaCare is a good piece of legislation, I will only discuss the matter with those who are willing to admit that there are valid free-market criticisms of the law. And so on, and so forth.
A conversation is a place in another person's life. You have to earn a place in my conversations just as you have to earn a place at my dinner table. You have to demonstrate good faith and a desire to connect. If you don't, it doesn't mean you're a bad person, and it certainly doesn't mean that you're wrong.
But it does mean that I won't be discussing it with you.