Will Neo-Nazism be a serious problem in the 21st century?

[TNF]

Depends on how the economic crises of this century are resolved. Fascism is a response to the left, so if you don't have anything approximating the victory of the Bolsheviks in this century, I don't think you'll see a far-right group attain power anywhere. Perhaps the greatest threat of neo-Nazi resurgence is in Greece, in the form of Golden Dawn, especially given the total inability of Syriza to do much of anything to address the crisis.

[TNF]

antisemitism will always be a problem, unfortunately.

Only so long as class society, which produces it and uses it to divide the public into easily exploitable groups, exists.