The uk doesnt really count, because it also has a fttp election system for the parliament, there are always 2 big parties and then some minor ones.
Better example would be Germany.
There were 7 major political parties in Germany in 1933, so I’m unsure that there is overwhelming evidence that more than 2 political parties is protective against extremism.
There were 7 major political parties in Germany in 1933, so I’m unsure that there is overwhelming evidence that more than 2 political parties is protective against extremism.