Remember that Life photo of Richard Nixon in a garden coyly sporting a copy of Collected Stories of William Faulkner under his arm? Well, that picture started Richard Stern to thinking that Nixon was worth a story and he set out to interview him. The subsequent events, as recorded in ""The Pursuit of Washington,"" proved to Stern that Nixon was no long-suffering intellectual but a man who had traveled an awesome distance from himself, until the real Nixon was lost in a jerry-built political image. This is one of the best stories in Stern's collection of fiction, non-fiction and a three-act play. The play is a pleasant piece of showshop on the Samuel French, straw-hat level, bright but not cutting. (It is about a man who invents incredible games and lives on an island; his three daughters have their own game of marital merry-go-round.) The short stories are written in a hammered mandarin style, rich as a gong. Their ironies are mainly verbal but fun.