I live in the state of California in the United States, which is a hot bed of referendums. We are going to have, at the beginning of November, I don't know how many state referendums and local referendums, but I think it's something like 20 or 25. I've become quite skeptical about referendums.
With regard to the specific issue of proportional representation, one thing I would point out is that 150 years ago there was not a single country that had PR. It has been adopted by many countries since then and, obviously today, proportional representation is now the most widely used system. It was adopted without a referendum by almost all of these countries. There are a few exceptions. I think Switzerland is one, but Switzerland is a referendum addicted country, and almost everything is done by referendum in Switzerland.
I've observed a lot of referendums on many different issues, especially since I've lived in California for many decades now. I am skeptical because outcomes of referendums are often highly volatile and unpredictable. They often involve a lot of emotion, demagoguery, and outright lies, and I'm especially appalled at outcomes of referendums like the recent Brexit referendum in Britain, which shows how much damage a referendum can do. I think Brexit has been a disaster for Britain. It has been a disaster for Europe, and it has been a disaster for the whole world.
My opinion is that if one can avoid a referendum, please avoid it.