In the Line of Fire (1993)

Secret Service agents Frank Horrigan and Al D’Andrea meet with members of a counterfeiting group at a marina. The group’s leader, Mendoza, tells Horrigan that he has identified D’Andrea as an undercover agent, and forces him to prove his loyalty by putting a gun to D’Andrea’s head and pulling the trigger. When the gun just clicks, Horrigan then shoots and kills Mendoza’s men, identifies himself as an agent, and arrests Mendoza. Horrigan investigates a complaint from a landlady about an apartment’s absent tenant, Joseph McCrawley. He finds a collage of photographs and newspaper articles on famous assassinations, a model-building magazine, and a Time cover with the President’s head circled.

When Horrigan and D’ Andrea return with a search warrant, only one photograph remains, which shows a much younger Horrigan standing behind John F. Kennedy in Dallas in 1963, on the day Kennedy was assassinated. Horrigan is the only remaining active agent who was guarding the President that day, and he is wracked with guilt over his failure to react quickly enough to the first shot, shielding Kennedy from the subsequent fatal bullet, which could have saved the President’s life. This guilt drove Horrigan to drink excessively; and eventually his family left him.