Ending fascism, is never going to be legal mate. Fascism is a legalist doctrine - the very first thing they do is say everything they do is "legal" and everything you do to oppose them is not. That's kinda one of the ways you can historically tell its fascism because that's what they do.
So your plan is to elect Dems to... break the laws the Dems say are why they can't stop the Nazis?
Bad plan. Really fucking dumb actually.