Already happening. There are multiple far right militias emerging in Western Europe already. They do combat training and are developing a network that covers multiple countries, often attending eachothers actions. They receive funding from rich people and I suspect the CIA and openly share their visions of a white Europe.

Noticeable groups are Schild en Vrienden (an offspring of Vlaams Belang) from Belgium, Voorpost from BE and NL, Geuzenbond from NL and various German groups who frequently get together. To this day I have yet to see left wing groups like this emerging. I have expressed my concern on this topic to the party on multiple occasions without a result.

And then we have the standard far right parties who keep increasing in popularity, with the regular libs seeing it as a chance to move to the right.