Apologies for posting in English, but my German just isn't good enough 🙂

BOTH strategies don't work.

There are numerous examples of places where the extremists have been allowed to rule (Poland, Hungary, ...) and while they're clearly incompetent to a neutral observer, they are all of them populists who have carefully studied Göring. Don't be fooled by the stereotypical electorate, the leaders know exactly what they're doing. They mostly run on divide and conquer, and to divide they use us-vs-them politics where there is always another minority to blame.

Unfortunately, as a Flemish Belgian, I can tell you that isolating them doesn't work either. Ever since "black Sunday" in the 90s, we've had the "cordon sanitaire" around the Vlaams Blok. They have in the mean time been found guilty of racism and forcibly disbanded, and they just restarted as Vlaams Belang. The cordon sanitaire doesn't really help: they just use it as ammunition in their rallying cries against the status quo, and it just adds an underdog aspect to them. People do like an underdog.

By now we've come to the point where for ver m several election cycles, the less extreme NVA (right-wing nationalists) have repeatedly made tentative ouvertures to be willing to govern with VB as long as they "clean up the ranks" first; and the fear is that VB will at one point be so big that it will be impossible to form a majority without them.

We obviously need to fight these ideas, but forbidding them it's no more a solution than letting it run it's course. It looks like the only way through is proper education, but that's a process of decades... And of course anything right-wing doesn't like good education, as people who know history and can think clearly don't vote for them.