Being There (1979)

Chance, a gardener who knows nothing of the world beyond television, is turned out on to the streets of Washington and mistaken for a sage. His remarks about the seasons are heard as economic policy, and within weeks he is advising the president. Peter Sellers plays him with total stillness, the opposite of his usual tricks, and Melvyn Douglas won an Oscar as the dying kingmaker who adopts him. The target is a political class that hears what it wants in any calm voice. Slow and quiet by design; patience is repaid.