The problem with that approach is that it can also be applied by governments/authorities who are threatened by legitimate challenge. Like when they wanted the leadership election debates to only include Tories, labour and lib Dems. There are other legitimate options out there.
I dont see that. Why would isolating groups with policies that clearly encourage hatred and violence toward certain ethnic and religious groups stop the environmentalists, socialists, libertarians etc etc from forming parties and taking part in "mainstream" debate?
He wasn't though mate. Hitler never got elected to any position in his life. He lost the 1932 presidential elections to Hindenburg by a comfortable margin. There's an awful lot of complicated issues that built up to Hitler stealing power but him being elected was not one of them.
He finished second place by a resounding margin in a three horse race were hardly anyone wanted the communists in. Hindenburg had 53% of the vote, Hitler 36.8% and Ernst Thalmann of the KPG (communist party) had 10.2%. He was soundly beaten. It was nothing short of a disgrace that he was able to menouve himself into such a position and only gross incompetence from Hindenburg, Von Pappen and the wider Reichstag not to mention the people themselves along with wilful disregard for democracy and process from everyone else made it possible. There was absolutely nothing democratic about that monsters rise to power.
Gets 36.8% of the vote in a three horse race were even the communists party managed 10.2% and was still beaten by a comfortable margin of 16%.
But that's not what you said though is it? Not once have I claimed that 36.8% of the turnout voting for an evil party who among other things were violently anti-semitic like Nazis was not a problem. It's terrifying that they even managed 0.1%.