Fascism is not a coherent single ideology but a collage of contradictory features; a political movement can be called fascist if it exhibits even one or two of these recurring traits, around which a fascist whole can coagulate. Because the features contradict each other, the pattern is a 'fuzzy totalitarianism,' recognizable by family resemblance rather than by a fixed definition.
Fascism can be detected through a checklist of recurring symptoms: the cult of tradition, rejection of modernism, action for action's sake, intolerance of disagreement as treason, fear of difference, appeal to a frustrated middle class, obsession with a plot, humiliation by enemies who are simultaneously too strong and too weak, life as permanent warfare, contempt for the weak, cult of heroism tied to death, machismo, selective populism, and an impoverished 'Newspeak.' Any one feature appearing in public life is enough to warrant vigilance.
Fascist populism invents a 'People' as a monolithic entity expressing a Common Will, which the Leader alone interprets, so individuals lose their delegating power and become merely a stage audience. This 'qualitative populism' lets a ruler bypass parliamentary democracy by claiming to voice the people directly, a mechanism Eco warns can recur through new media even without classic fascist trappings.
Eco recounts being a boy in Italy when partisans entered his town and the fascist regime collapsed; he saw armed partisans of different political factions, and a partisan spokesman spoke of soldiers who died for freedom. This lived memory of liberation grounds his later claim that freedom and liberation are an unending task, and that fascism can return in everyday, unrecognized forms.
Fascist regimes rely on a limited, simplified language ('Newspeak') that restricts the vocabulary available for complex and critical reasoning, so that popular talk shows and simplistic media patter can serve the same function of narrowing thought. Watching how public language shrinks becomes a way to detect authoritarian tendencies before they take institutional form.