Right at the beginning of The March On Rome, a special screening in the Venice Days section of the Venice Film Festival, Mark Cousins draws our collective gaze to a piece of graffiti saying that cinema is most powerful weapon of all. It isn’t clear — to me, anyway — whether that joyful proclamation dates back to 1922, when Benito Mussolini led a Fascist march from Naples to Rome, or to some other eruption of historical optimism. Cinema isn’t as powerful as all that — if it were, Fascism would have been clobbered to a pulp by Chaplin, Lubitsch and all the other filmmakers who lampooned its vainglorious leaders. But images do matter. They certainly mattered to Italian Fascism.