SUNDAY The Mission (NBC, 9-11 p.m.): Robert De Niro and Jeremy Irons are two Jesuit priests on an 18th-century mission in the Brazilian jungles, in the network premiere of this 1986 film. Its rich visual imagery won it an Oscar for cinematography, but what it's really about is the moral challenge the priests face as they try to decide how to save the Indians.
The New Range Wars (TBS cable, 10-11 p.m.): Cattle grazing on public land - one of the hottest issues in a traditionally hot field, the environment - is explored in this "World of Audubon" documentary. Actor Peter Coyote is host as the two positions are analyzed: ranchers with their livelihood - and profits - at stake vs. reform-minded ecologists.
State of the Natural World
(Discovery cable, 10-11 p.m.): Infernal scenes of the Persian Gulf today - burning wells, giant spills - make grim viewing in "Legacy of War," the first of of a six-part series. But it draws a startling inference: The Gulf may not turn out to be quite the environmental apocalypse many expect. In all, though, it's a sad spectacle that emerges as the documentaries take their multifaceted look at our physically deteriorating planet. (Aired on consecutive nights).
...Talking With David Frost
(PBS, 8-9 p.m.): Now that she's out of office, this week's guest, former British Prime Minister Margaret Thatcher, can speak a lot more freely - especially to a cordial host so skilled in eliciting newsworthy comments. The session covers Thatcher's historic years in office, current affairs like the Persian Gulf, and a few less obvious topics.
Please check local listings, especially on PBS.