The Kidnapping of the President (1980)

A South American quasi-revolutionary/guerilla/terrorist and a misled, admiring girl compatriot manage to kidnap the U.S. President during a diplomatic visit to Toronto. With a nondescript armored truck, crudely yet somehow elaborately rigged with high explosives (and the President trapped inside), the two terrorists keep the Secret Service at bay until in the end, Assanti is killed and Shatner has to find a way into the truck anyway.