Paul Schrader was in meltdown in 1972. Drinking heavily, living in his car, he was hospitalised with a gastric ulcer. There he read about Arthur Bremer's attempt to assassinate Alabama Governor George Wallace: the story was the germ of his screenplay for Taxi Driver (1976). Executives at Columbia hated the script, but when Martin Scorsese and Robert De Niro, who were flying high after the triumphs of Mean Streets (1973) and The Godfather Part II (1974),...