Europe has shown how to deal with far right parties.
Let them be elected then let them fail spectacularly.
Austria - Haider was perhaps successful but after his death there were a LOT of allegations came out about him.
Germany - Far Right coalition government in Hamburg fell apart after the "law and order" party leader was caught taking cocaine and partying all night with prostitutes.
The problem with these parties is that they are often headed by megalomaniac who shoot themselves in the foot when given a tiny bit of power.
The 5% rule works very well and if a party gets more than 5% then it should be represented in parliament, no matter how distasteful we find them.
To say that the Nazi party would get into power if they got 5% is absolutely ridiculous, for the simple reason that they are banned in Germany. And any party spouting Nazi paroles would be too.