I would add that extremism of any kind will never get full support of most of the population, so whenever they get any kind of power, it leads to the same authoritarian patters, brutal targetting of opposition, elimination of plurality of opinion, all-encompassing propaganda etc.
Extremism leads to structures which are antithetic to freedom, basically.
While they don’t get the same support, because they are so extreme, they get the most attention … in the press, in social media, in the general zeitgeist. They hover above all conversations and pollute downstream goal and choices.
I think it’s only once it gains mindset and traction does the forcers of Democracy kick into gear; the trick is to move democracy forward quickly before traction becomes entrenchment (like the Supreme Court).