Harris, ex-Senator from Oklahoma, ex-Presidential candidate, has written effectively about his hopes for returning America to the people and wresting economic control from the oil, steel, and automobile monopolies in The New Populism (1973) and Alarms and Hopes (1968). His new book, an envoi to Washington, is more gossipy and indulgent as Harris recalls his initiation to that mesmerizing city. Much of the chatter here is about personalities and much of it is insipid (""I thought Robert Kennedy was a little too fond of dogs""). Proud of his work on the Kerner Commission, Harris admits to somewhat belated opposition to the Vietnam War--he was preoccupied with domestic justice. He and his Indian wife LaDonna, admirers of both RFK and Hubert Humphrey, were ""on the spot"" in 1968 when the two men decided to enter the race; they finally chose to back HHH, ""the most important and effective national legislator of this generation."" As to his own Presidential campaign--he fought the good fight and lost. Money was the spoiler since on the issues ""I invariably came off best. . . ."" ""Not that this is sour grapes, just a touch of regret for what might have been. Harris is always genial and quite rightly disclaims Time magazine's ""radical"" label. All he really stands for is ""a return to basic principles of Americanism."" The cliche makes rather a disappointing exit line.