In Bruno Barreto’s unintentionally cartoonish One Tough Cop, Amy Irving plays a prim federal agent out to blackmail Bo Dietl (Stephen Baldwin), made out to be the one honest policeman left in New York. Dietl was a real cop, but how much of the onscreen story is true isn’t clear, since we’re told that all the other characters are fictitious. The plot and dialogue are pure cliché, meaning either that life imitates B movies or that Dietl’s career has been as shabbily served artistically as it was by his department. When Dietl refuses to cooperate with a sting operation, the feds threaten to expose him as corrupt. At the same time, while he and his partner crack a high-profile case involving the sexual abuse and mutilation of a nun,his superiors claim the credit. Baldwin plays Dietl with a straight face, even when this bruiser spouts such sentiments as “I always hated it when people would hurt other people.” As Dietl’s compulsive-gambler partner, Chris Penn is equally phlegmatic. The actors try to inject heart into the film, but the surrounding cardboard defeats them.