In The Line Of Fire (1993)

Frank Horrigan (Clint Eastwood), an aging Secret Service agent, discovers a plot to assassinate the current president when a man, calling himself Booth (John Malkovich) calls him and tells him that he admires Frank for his flair and style on the job and that he plans on killing the president. Frank manages to discover that the caller is Mitch Leary a former CIA operative who has gone off the deep end and become a psychopathic killer. Frank makes it his mission to track down and stop Leary in his attempts to assassinate the president, which isn't much trouble as Leary seems intent on involving Frank in the plot all throughout the ordeal. Will Frank be able to save the president from falling under Leary's assassination plot?