The "fascism" word is popping up quite a bit in progressive analyses of Donalp Trump and and his followers, some of whom clearly have a neo-Brownshirt.
Digby takes a pass at it in On the "F" word Hullabaloo 11/24/2015
I generally avoid using "fascism" for current groups because defining it does turn out to be very tricky. We can be sure with Mussolini, because he actually called his movement Fascist. There's even a long-running debate in history and political science about whether Hitler's government should be called fascist versus seeing the Nazi regime as a qualitatively different kind of dictatorship. I'm okay with calling it fascist just because that's what most of the world called it at the time.
My own operative definition of fascism is the same as Justice Potter Stewart's famous definition of pornography, "I know it when I see it." And I do see it in Trump's movement.
Bob Kuttner gives it a shot in America's Political Landscape Providing Fresh Soil for Fascism Alternet 11/23/2015.