Dear Mary: Do I have a moral duty to allow Brexit chat at supper parties?

Q. I’ve been having friends to supper for many decades. Although I say it myself, these gatherings have often been hugely successful, with lots of laughter, people making new friends and guests regularly staying beyond 1 a.m. When Brexit started it was OK because talk of it didn’t dominate the evening. It now does. Last week I told my guests the subject was banned. They looked thrown but we went on to have an enjoyable evening. On the other hand I am also wondering, is it my duty — as someone with a venue and a good network of friends — to allow my guests to hold forth at this time of what some might call a National Emergency?
— R.G., London W8

A. You are right to have banned it. Brexit conversation seems to be uniquely undialectical in that participants don’t wish to arrive at a truth through listening to reasoned arguments.